Temporal Expression Research Articles

Antibody Preparation, Protein Expression, and Function Analysis of Cyp19a1b in Ovarian Differentiation in a Natural Triploid Teleost Qi River Crucian Carp (Carassius auratus)

Estrogen is an essential sex steroid that functions in numerous biological systems including female reproduction, neuroendocrine, vascular, skeletal, and immune systems. The synthesis of estrogen is controlled by the rate-limiting enzyme, which has been confirmed to exist in two different forms, named brain aromatase and ovary aromatase, and encoded by cyp19a1a and cyp19a1b respectively in teleosts. However, existing studies have primarily focused on the expression and function of cyp19a1b in the brain and cyp19a1a in the gonad, the roles of cyp19a1b in the female gonad of teleosts are largely unknown. In our previous study, we cloned the full length of the cyp19a1b gene from a natural triploid teleost Qi River crucian carp (Carassius auratus), andthe spatial and temporal expression patterns of cyp19a1b mRNA were detected. To further clarify the roles of cyp19a1b in the ovarian differentiation of Qi River crucian carp, we produced a polyclonal antibody of Cyp19a1b in this study. Western blotting results showed that Cyp19a1b was mainly expressed in the brain and then in the ovary, heart, liver, and muscle. During embryogenesis, Cyp19a1b was abundantly expressed in the neurula stage. Immunohistochemistry demonstrated that Cyp19a1b was expressed in the radioactive glial cells (RGCs) of the brain from 20 days after hatching (dah) and the somatic cells of the ovaries from 30 dah, the critical period of ovarian differentiation in Qi River crucian carp. With the treatment of letrozole, an inhibitor of the aromatase, the expression of Cyp19a1b was downregulated both in the brain and gonad. Our results suggested that Cyp19a1b might be involved in the development of the nervous system and also participate in the ovarian differentiation of Qi River crucian carp.

Genomic insights into genes expressed specifically during infancy highlight their dominant influence on the neuronal system

BackgroundElucidating the dynamics of gene expression across developmental stages, including the genomic characteristics of brain expression during infancy, is pivotal in deciphering human psychiatric and neurological disorders and providing insights into developmental disorders.ResultsLeveraging comprehensive human GWAS associations with temporal and spatial brain expression data, we discovered a distinctive co-expression cluster comprising 897 genes highly expressed specifically during infancy, enriched in functions related to the neuronal system. This gene cluster notably harbors the highest ratio of genes linked to psychiatric and neurological disorders. Through computational analysis, MYT1L emerged as a potential central transcription factor governing these genes. Remarkably, the infancy-specific expressed genes, including SYT1, exhibit prominent colocalization within human accelerated regions. Additionally, chromatin state analysis unveiled prevalent epigenetic markers associated with enhancer-specific modifications. In addition, this cluster of genes has demonstrated to be specifically highly expressed in cell-types including excitatory neurons, medial ganglionic eminence and caudal ganglionic eminence.ConclusionsThis study comprehensively characterizes the genomics and epigenomics of genes specifically expressed during infancy, identifying crucial hub genes and transcription factors. These findings offer valuable insights into early detection strategies and interventions for psychiatric and neurological disorders.

Membrane Interactions of GET1 and GET2 Facilitate Fiber Cell Initiation through the Guided Entry of the TA Protein Pathway in Cotton.

The guided entry of TA proteins (GET) pathway, which is responsible for the post-translational targeting and insertion of the tail-anchored (TA) protein into the endoplasmic reticulum (ER), plays an important role in physiological processes such as protein sorting, vesicle trafficking, cell apoptosis, and enzymatic reactions in which the GET1/2 complex is indispensable. However, a comprehensive study of the GET1 and GET2 genes and the GET pathway in cotton has not yet been carried out. Here, 12 GET1 and 21 GET2 genes were identified in nine representative plant species, and the phylogenetic relationships, gene structures, protein motifs, cis-regulatory elements (CREs), and temporal and spatial expression profiles were analyzed thoroughly. Our study indicated that GhGET1s and GhGET2s might be localized on ER membranes. According to expression profiling and CREs analysis, GhGET2-A02 was identified as a promising candidate for fiber cell development, interacting with two GhGET1s in the membrane, with a binding bias toward GhGET1-A06. Silencing of GhGET1-A06 or GhGET2-A02 reduced fiber initiation and elongation. In summary, our research provides important evidence for understanding the gene families and functions of GET1 and GET2 in cotton and provides clues for molecular breeding of high-quality cotton fiber varieties.

Molecular characterization of a novel thioredoxin-related transmembrane protein gene AcTMX3 that plays important roles in antioxidant defence in Arma chinensis diapause.

Protein disulphide isomerase (PDI) possesses disulphide isomerase, oxidoreductase and molecular chaperone activities, and is involved in regulating various physiological processes. However, there are few studies on the function in insect diapause. In this study, we cloned one novel member PDI family (TMX3, thioredoxin-related transmembrane protein 3) in Arma chinensis. The AcTMX3 encodes 426 amino acids that contains a predicted N-terminal signal sequence, a thioredoxin-like domain with the CXXC active site and a potential transmembrane region, which are typical sequence features of TMX3. RT-qPCR results showed that AcTMX3 was mainly expressed in the head under non-diapause conditions, while AcTMX3 was highly expressed in the fat body (central metabolic organ) under diapause conditions. Moreover, temporal expression profile showed that compared with non-diapause conditions, diapause conditions significantly induced AcTMX3 expression, and the expression of AcTMX3 was enhanced at 15°C. Silencing AcTMX3 in A. chinensis significantly inhibited the expression of antioxidant genes (AcTrx2 and AcTrx-like), increased the content of H2O2 and ascorbate and reduced the survival rate of A. chinensis under diapause conditions. Our results suggested that AcTMX3 played an important role in the resistance of A. chinensis to oxidative stress under diapause conditions.

Analyzing super-enhancer temporal dynamics reveals potential critical enhancers and their gene regulatory networks underlying skeletal muscle development.

Super-enhancers (SEs) govern the expression of genes defining cell identity. However, the dynamic landscape of SEs and their critical constituent enhancers involved in skeletal muscle development remains unclear. In this study, using pig as a model, we employed CUT&Tag to profile the enhancer-associated histone modification marker H3K27ac in skeletal muscle across two prenatal and three postnatal stages and investigated how SEs influence skeletal muscle development. We identified three SE families with distinct temporal dynamics: continuous (Con, 397), transient (TS, 434), and de novo (DN, 756). These SE families are associated with different temporal gene expression trajectories, biological functions, and DNA methylation levels. Notably, several lines of evidence suggest a potential prominent role of Con SEs in regulating porcine muscle development and meat traits. To pinpoint key cis-regulatory units in Con SEs, we developed an integrative approach that leverages information from eRNA annotation, GWAS signals and high-throughput capture STARR-seq experiments. Within Con SEs, we identified 20 candidate critical enhancers with meat and carcass-associated DNA variations that affect enhancer activity and inferred their upstream TFs and downstream target genes. As a proof of concept, we experimentally validated the role of one such enhancer and its potential target gene during myogenesis. Our findings reveal the dynamic regulatory features of SEs in skeletal muscle development and provide a general integrative framework for identifying critical enhancers underlying the formation of complex traits.

Toxicity of nuclear-localized GFP in reporter mice

Various techniques using fluorescent reporter probes have been developed, such as GFP transgenic mouse lines that are used to detect spatial–temporal expression levels of genes. Although GFP expression is largely considered non-toxic, recent reports have indicated that under certain conditions GFP can display cellular toxicity. We hereby report the nuclear toxicity of H2B-GFP using a K14 specific Tet-on reporter mouse system. Using this system, GFP accumulates in the nucleus of all K14 expressing cells, such as the ocular surface epithelia and ocular adnexa. Expression of high levels of nuclear GFP during embryonic stages led to an eye open-at-birth (EOB) phenotype and abnormal ocular adnexa development and during adult and aging stages showed notable toxicity to ocular tissues. Other tissues, such as skin, also presented multiple defects associated with H2B-GFP expression. This toxicity was found to be concentration dependent, with homozygous mice presenting extremely high toxicity, while heterozygous mice presented limited toxicity. Upon induction, the accumulation of H2B-GFP in the nucleus of homozygous mice led to apoptosis within 2 weeks. This study therefore shows that although the use of nuclear GFP reporter mice is a valuable tool, at high levels, nuclear GFP can be toxic, leading to cell death and affecting tissue function.

Circadian plasticity evolves through regulatory changes in a neuropeptide gene.

Many organisms, including cosmopolitan drosophilids, show circadian plasticity, varying their activity with changing dawn-dusk intervals1. How this behaviour evolves is unclear. Here we compare Drosophila melanogaster with Drosophila sechellia, an equatorial, ecological specialist that experiences minimal photoperiod variation, to investigate the mechanistic basis of circadian plasticity evolution2. D. sechellia has lost the ability to delay its evening activity peak time under long photoperiods. Screening of circadian mutants in D. melanogaster/D. sechellia hybrids identifies a contribution of the neuropeptide pigment-dispersing factor (Pdf) to this loss. Pdf exhibits species-specific temporal expression, due in part to cis-regulatory divergence. RNA interference and rescue experiments in D. melanogaster using species-specific Pdf regulatory sequences demonstrate that modulation of this neuropeptide's expression affects the degree of behavioural plasticity. The Pdf regulatory region exhibits signals of selection in D. sechellia and across populations of D. melanogaster from different latitudes. We provide evidence that plasticity confers a selective advantage for D. melanogaster at elevated latitude, whereas D. sechellia probably suffers fitness costs through reduced copulation success outside its range. Our findings highlight this neuropeptide gene as a hotspot locus for circadian plasticity evolution that might have contributed to both D. melanogaster's global distribution and D. sechellia's specialization.

Comparative analysis of the physiological and transcriptomic profiles reveals alfalfa drought resistance mechanisms

BackgroundDrought stress is a major limiting factor that affects forage yields, and understanding the drought resistance mechanism of plants is crucial for improving crop yields in arid areas. Alfalfa (Medicago sativa L.) is the most important legume plant, mainly planted in arid and semi-arid areas. However, the adaptability of alfalfa to drought stress and its physiological and molecular mechanisms of drought resistance remains unclear.ResultsIn this study, we analyzed the physiological and transcriptome responses of alfalfa cultivars with different drought resistances (drought-sensitive Gannong No. 3 (G3), drought-resistant Gannong No. 8 (G8), and strong drought-resistant Longdong (LD)) under drought stress at 0, 6, 12, and 24 h. LD had higher catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities and a higher soluble protein content, lower malondialdehyde (MDA) content, a lower O2·− production rate, and a lower H2O2 content than G8 and G3 (P < 0.05). The functional enrichment analysis, temporal expression pattern analysis, and weighted gene co-expression network analysis (WGCNA) of the differentially expressed genes (DEGs) showed phenylpropanoid biosynthesis, flavonoid biosynthesis, starch and sucrose metabolism, glycolysis/gluconeogenesis, glutathione metabolism, and biosynthesis of amino acid responses to drought stress in alfalfa. The differential expression of genes during phenylpropanoid biosynthesis, starch and sucrose metabolism, and the glutathione metabolism pathway was further studied, and it was speculated that PAL, COMT, 4CL, CCR, CAD, HXK, INV, SUS, WAXY, AGP, GST, and APX1 played important roles in the alfalfa drought stress response.ConclusionsThe aim of this study was to enhance alfalfa drought resistance by overexpressing positively regulated genes and knocking out negatively regulated genes, providing genetic resources for the subsequent molecular-assisted breeding of drought-resistant alfalfa crops.

Characterizing virulence differences in a parasitoid wasp through comparative transcriptomic and proteomic

BackgroundTwo strains of the endoparasitoid Cotesia typhae (Hymenoptera: Braconidae) present a differential parasitism success on the host, Sesamia nonagrioides (Lepidoptera: Noctuidae). One is virulent on both permissive and resistant host populations, and the other only on the permissive host. This interaction provides a very interesting frame for studying virulence factors. Here, we used a combination of comparative transcriptomic and proteomic analyses to unravel the molecular basis underlying virulence differences between the strains.ResultsFirst, we report that virulence genes are mostly expressed during the pupal stage 24 h before adult emergence of the parasitoid. Especially, 55 proviral genes are up-regulated at this stage, while their expression is only expected in the host. Parasitoid gene expression in the host increases from 24 to 96 h post-parasitism, revealing the expression of 54 proviral genes at early parasitism stage and the active participation of teratocytes to the parasitism success at the late stage. Secondly, comparison between strains reveals differences in venom composition, with 12 proteins showing differential abundance. Proviral expression in the host displays a strong temporal variability, along with differential patterns between strains. Notably, a subset of proviral genes including protein-tyrosine phosphatases is specifically over-expressed in the resistant host parasitized by the less virulent strain, 24 h after parasitism. This result particularly hints at host modulation of proviral expression. Combining proteomic and transcriptomic data at various stages, we identified 8 candidate genes to support the difference in reproductive success of the two strains, one proviral and 7 venom genes, one of them being also produced within the host by the teratocytes.ConclusionsThis study sheds light on the temporal expression of virulence factors of Cotesia typhae, both in the host and in the parasitoid. It also identifies potential molecular candidates driving differences in parasitism success between two strains. Together, those findings provide a path for further exploration of virulence mechanisms in parasitoid wasps, and offer insights into host-parasitoid coevolution.

12547 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&amp;S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

9246 Mineralocorticoid Receptor Regulation of the Molecular Clock in Cardiomyocytes Is Modulated by Time of Day

Abstract Disclosure: M. Kanki: None. S. Heanue: None. P.J. Fuller: None. T.J. Cole: None. C.D. Clyne: None. M.J. Young: None. The onset of cardiovascular disease events peaks in the early morning, which coincides with the diurnal surge in aldosterone and cortisol. Aldosterone-induced mineralocorticoid receptor (MR) activation in cardiomyocytes has established roles in cardiac pump function and electrophysiology and inappropriate MR activation promotes cardiovascular pathophysiology in experimental models of hypertension and heart failure and in the clinic. Recently, we identified a novel role for MR in regulating the circadian clock signalling network in cardiac cells and showed that time of day modulates MR activation in the heart. Whether time-of-day-dependent MR regulation of circadian clocks in cardiomyocytes modulates temporal expression of key functional pathways is unknown. Therefore, we sought to identify cardiac responsiveness to MR stimulation at lights on (7AM) versus lights off (7PM) in ≥8-week old male wildtype (WT) and cardiomyocyte-MR knockout (MyoMRKO) mice. RNA-seq analyses revealed that aldosterone (50 ug/kg) administered at 7PM but not at 7AM significantly enriched transcription of genes associated with 52 biological processes including “Circadian rhythm”, “Reg. of blood pressure”, “Ion transport” and “Reg. of the force of heart contraction” in WT hearts (p&amp;lt;0.05 versus 7PM vehicle-injected WT mice). These outcomes were absent in hearts isolated from MyoMRKO mice administered aldosterone at 7AM or 7PM. Analysis by RT-qPCR revealed that aldosterone versus vehicle administered at 7AM increased expression of circadian Period (Per) and Thyrotroph embryonic factor (Tef) genes in WT hearts, which was lost in MyoMRKO mice. Whole transcriptome analysis also detected significant enrichment in “Cell-cell signalling”, “Positive regulation of cell differentiation”, “Positive regulation of glucose metabolic process”, “Regulation of sodium ion transport”, and “Inflammatory response" processes between 7AM and 7PM in WT hearts, which was also lost in MyoMRKO mice. Our data show that MR transcription of genes associated with circadian rhythms and ion transport is temporally regulated, and demonstrates specificity for cardiomyocyte-MR regulation of circadian clocks. Taken together, we highlight that the role for cardiomyocyte-MR regulation of cardiac electrophysiology, heart rate variability, and metabolic processes is time-of-day-dependent. Understanding temporal coordination of MR activation in physiology and pathophysiology may inform new strategies for optimising MR-directed therapies in patients with heart disease. Presentation: 6/2/2024

12547 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&amp;S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

7763 Mineralocorticoid Receptor Regulation of the Molecular Clock in Cardiomyocytes Is Modulated by Time of Day

Abstract Disclosure: M. Kanki: None. S. Heanue: None. P.J. Fuller: None. T.J. Cole: None. C.D. Clyne: None. M.J. Young: None. The onset of cardiovascular disease events peaks in the early morning, which coincides with the diurnal surge in aldosterone and cortisol. Aldosterone-induced mineralocorticoid receptor (MR) activation in cardiomyocytes has established roles in cardiac pump function and electrophysiology and inappropriate MR activation promotes cardiovascular pathophysiology in experimental models of hypertension and heart failure and in the clinic. Recently, we identified a novel role for MR in regulating the circadian clock signalling network in cardiac cells and showed that time of day modulates MR activation in the heart. Whether time-of-day-dependent MR regulation of circadian clocks in cardiomyocytes modulates temporal expression of key functional pathways is unknown. Therefore, we sought to identify cardiac responsiveness to MR stimulation at lights on (7AM) versus lights off (7PM) in ≥8-week old male wildtype (WT) and cardiomyocyte-MR knockout (MyoMRKO) mice. RNA-seq analyses revealed that aldosterone (50 ug/kg) administered at 7PM but not at 7AM significantly enriched transcription of genes associated with 52 biological processes including “Circadian rhythm”, “Reg. of blood pressure”, “Ion transport” and “Reg. of the force of heart contraction” in WT hearts (p&amp;lt;0.05 versus 7PM vehicle-injected WT mice). These outcomes were absent in hearts isolated from MyoMRKO mice administered aldosterone at 7AM or 7PM. Analysis by RT-qPCR revealed that aldosterone versus vehicle administered at 7AM increased expression of circadian Period (Per) and Thyrotroph embryonic factor (Tef) genes in WT hearts, which was lost in MyoMRKO mice. Whole transcriptome analysis also detected significant enrichment in “Cell-cell signalling”, “Positive regulation of cell differentiation”, “Positive regulation of glucose metabolic process”, “Regulation of sodium ion transport”, and “Inflammatory response" processes between 7AM and 7PM in WT hearts, which was also lost in MyoMRKO mice. Our data show that MR transcription of genes associated with circadian rhythms and ion transport is temporally regulated, and demonstrates specificity for cardiomyocyte-MR regulation of circadian clocks. Taken together, we highlight that the role for cardiomyocyte-MR regulation of cardiac electrophysiology, heart rate variability, and metabolic processes is time-of-day-dependent. Understanding temporal coordination of MR activation in physiology and pathophysiology may inform new strategies for optimising MR-directed therapies in patients with heart disease. Presentation: 6/2/2024

12674 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&amp;S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

12674 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&amp;S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

8490 The mRNA for the Nonsyndromic Deafness Gene Atp2b2 Is Reduced Following Developmental Hypothyroidism

Abstract Disclosure: E.A. Gregersen: None. R.P. Peeters: None. D. Forrest: None. D.S. Sharlin: None. Thyroid hormone (TH) is essential for auditory system development. In rodent models, low levels of TH during the early postnatal period delay cochlear tissue remodeling and alter ion channel function required for normal auditory function. TH receptors are ligand-dependent transcription factors that regulate gene expression. Considering this, auditory deficits observed in hypothyroidism are thought to be largely the result of altered expression of specific TH target genes. However, few TH-regulated genes in the developing cochlea have been reported. TH is reported to impact calcium signaling in several tissues, but whether regulators of calcium signaling are altered following developmental hypothyroidism in the cochlea is largely unexplored. In this report, we investigated the spatial and temporal expression of the ATPase, Ca++ transporting, plasma membrane 2 (Atp2b2) gene in a mouse model of developmental hypothyroidism. Timed-pregnant dams were treated with thyroid gland inhibitors to induce developmental TH insufficiency from embryonic day 12.5 (E12.5) through post-natal day 15 (P15). Untreated timed-pregnant dams served as euthyroid controls. Control and experimental cochleae were collected over a developmental period ranging from embryonic day 18.5 (E18.5) through P15. Cochleae were then processed to detect Atp2b2 mRNA by in situ hybridization or quantitative real-time PCR. In situ hybridization showed that Atp2b2 localizes to inner and outer hair cells as expected, but Atp2b2 was also observed at lower levels in the greater epithelial ridge and spiral ganglion. Quantification of Atp2b2 mRNA revealed an effect of postnatal day and treatment on Atp2b2. In euthyroid animals, Atp2b2 expression gradually increased until P10, then decreased slightly by P15. In hypothyroid animals, Atp2b2 mRNA was consistently decreased (2-2.5 fold). Hypothyroidism similarly impacted expression regardless of sex. The reduction in Atp2b2 mRNA expression in the hypothyroid animals suggests that Atp2b2 is developmentally regulated in part by thyroid hormone signaling. This study characterizes the relationship between TH and Atp2b2 expression during early cochlear development while providing insight into abnormal cochlear development due to hypothyroidism. Presentation: 6/3/2024

A new Bowman-Birk type protease inhibitor regulated by MeJA pathway in maize exhibits anti-feedant activity against the Ostrinia furnacalis.

Jasmonic acid (JA), an important plant hormone, plays a crucial role in defending against herbivorous insects. In this study, we have identified a new Bowman-Birk type protease inhibitor (BBTI) protein in maize that is regulated by the JA pathway and exhibits significant antifeedant activity, which is notably induced by exogenous Methyl Jasmonate and Ostrinia furnacalis feeding treatments. Bioinformatics analysis revealed significant differences in the BBTI protein among different maize inbred lines, except for the conserved domain. Prokaryotic and eukaryotic expression systems were constructed and expressed, and combined with bioassays, it was demonstrated that the antifeedant activity of BBTI is determined by protein modifications and conserved domains. Through RT-qPCR detection of BBTI and JA regulatory pathway-related genes' temporal expression in different maize inbred lines, we identified the regulatory mechanism of BBTI synthesis under the JA pathway. This study successfully cloned and identified the MeJA-induced anti-feedant activity gene BBTI and conducted functional validation in different maize inbred lines, providing valuable insights into the response mechanism of insect resistance induced by the plant JA pathway. The increased expression of the anti-feedant activity gene BBTI through exogenous MeJA induction may offer a potential new strategy for mediating plant defense against Lepidoptan insects.

PWWP3A deficiency accelerates testicular senescence in aged mice.

The PWWP domain-containing proteins are involved in chromatin-associated biological processes, including transcriptional regulation and DNA repair, and most of them are significant for gametogenesis and early embryonic development in mammals. PWWP3A, one of the PWWP domain proteins, is a reader of H3K36me2/H3K36me3 and a response factor to DNA damage. However, the physiological role of PWWP3A in spermatogenesis and fertility remains unclear. The goal of this study was to explore the function and mechanism of PWWP3A in the process of spermatogenesis. We generated V5-Pwwp3a KI mice and PWWP3A polyclonal antibody to observe the localization of PWWP3A in vivo. Meanwhile, Pwwp3a KO mice was used to explore the function in spermatogenesis. We reported that PWWP3A is a predominant expression in the testis of mice. During spermatogenesis, PWWP3A exhibits the temporal expression from early-pachytene to the round spermatids. The results of spermatocyte spreading and immunostaining showed that PWWP3A aggregated on the XY body, which then diffused as the XY chromosome separated at late-diplotene. Although the depletion of PWWP3A had no obvious reproductive defects in young male mice, there were observed morphological abnormalities in sperm heads. Immunoprecipitation demonstrated the interaction of PWWP3A with DNA repair proteins SMC5/6; however, PWWP3A deficiency did not result in any meiotic defects. Notably, the testes of aged male Pwwp3a KO mice displayed pronounced degeneration, and were characterized by the presence of vacuolated seminiferous tubules. Furthermore, RNA-seq analysis revealed an upregulation in the expression of genes which may be involving in immunoregulatory and inflammatory response pathways in aged Pwwp3a KO mice with testicular degeneration. Our study showed that PWWP3A was highly enriched in the mouse testis, and the Pwwp3a KO mice were fertile. However, the aged Pwwp3a KO male mice displayed testicular atrophy that may be due to changes in the immune micro-environment or abnormal repair of DNA damage.

Nighttime-specific differential gene expression in suprachiasmatic nucleus and habenula is associated with resilience to chronic social stress

The molecular mechanisms that link stress and biological rhythms still remain unclear. The habenula (Hb) is a key brain region involved in regulating diverse types of emotion-related behaviours while the suprachiasmatic nucleus (SCN) is the body’s central clock. To investigate the effects of chronic social stress on transcription patterns, we performed gene expression analysis in the Hb and SCN of stress-naïve and stress-exposed mice. Our analysis revealed a large number of differentially expressed genes and enrichment of synaptic and cell signalling pathways between resilient and stress-naïve mice at zeitgeber 16 (ZT16) in both the Hb and SCN. This transcriptomic signature was nighttime-specific and observed only in stress-resilient mice. In contrast, there were relatively few differences between the stress-susceptible and stress-naïve groups across time points. Our results reinforce the functional link between circadian gene expression patterns and differential responses to stress, thereby highlighting the importance of temporal expression patterns in homoeostatic stress responses.

Genome-wide identification of the grapevine β-1,3-glucanase gene (VviBG) family and expression analysis under different stresses.

The β-1,3-glucanase gene is widely involved in plant development and stress defense. However, an identification and expression analysis of the grape β-1,3-glucanase gene (VviBG) family had not been conducted prior to this study. Here, 42 VviBGs were identified in grapevine, all of which contain a GH-17 domain and a variable C-terminal domain. VviBGs were divided into three clades α, β and γ, and six subgroups A-F, with relatively conserved motifs/domains and intron/exon structures within each subgroup. The VviBG gene family contained four tandem repeat gene clusters. There were intra-species synteny relationships between two pairs of VviBGs and inter-species synteny relationships between 20 pairs of VviBGs and AtBGs. The VviBG promoter contained many cis-acting elements related to stress and hormone responses. Tissue-specific analysis showed that VviBGs exhibited distinct spatial and temporal expression patterns. Transcriptome analysis indicated that many VviBGs were induced by wounds, UV, downy mildew, cold, salt and drought, especially eight VviBGs in subgroup A of the γ clade. RT-qPCR analysis showed that these eight VviBGs were induced under abiotic stress (except for VviBG41 under cold stress), and most of them were induced at higher expression levels by PEG6000 and NaCl than under cold treatment. The chromosome localization, synteny and phylogenetic analysis of the VviBG members were first conducted. The cis-acting elements, transcriptome data and RT-qPCR analysis showed that VviBG genes play a crucial role in grape growth and stress (hormone, biotic and abiotic) responses. Our study laid a foundation for understanding their functions in grape resistance to different stresses.