Expression Of Transcription Factors Research Articles

PFOA substitute GenX at a sub-cytotoxic level exhibits thyroid-disrupting effects by inhibiting the expression of thyroid transcription factor 1.

While the occurrence of GenX, a novel alternative for perfluorooctanoic acid (PFOA), in the environment and its cytotoxicity at high concentrations to thyroid cells are well documented, limited information is available regarding its impact at low concentrations. GenX is detected to be as low as 0.001ng/mL in drinking water and 0.04-1ng/mL in human serum. In this study, we investigated the impact of GenX at levels similar to that from drinking water and human serum on thyroid function in vitro and in vivo. Our data showed that GenX from 0.001 to 0.1ng/mL was sub-cytotoxic and did not exhibit apparent impact on thyroid cell viability. However, GenX at 0.001ng/mL significantly reduced the expression of Thyroid Transcription Factor 1 (TTF-1) on both mRNA and protein levels. Further analysis showed that GenX suppressed TTF-1 expression through the inhibition of Wnt/β-catenin pathway. Furthermore, we tested as a proof-of-concept that inhibition of GSK-3β, a negative regulator in the Wnt/β-catenin pathway, using specific inhibitors could rescue GenX-induced TTF-1 reduction in thyroid cells. Together, our findings have not only provided evidence that GenX at a low but human exposure-relevant concentration could cause thyroid disruption, but also proposed potential underlying mechanism and treatment approach. This information will be useful for the guidance of the future use of GenX.

EIF2α phosphorylation-ATF4 axis-mediated transcriptional reprogramming mitigates mitochondrial impairment during ER stress.

Eukaryotic translation initiation factor 2α (eIF2α) phosphorylation, which regulates all 3 unfolded protein response pathways, helps maintain cellular homeostasis and overcome endoplasmic reticulum (ER) stress through transcriptional and translational reprogramming. However, transcriptional regulation of mitochondrial homeostasis by eIF2α phosphorylation during ER stress is not fully understood. Here, we report that the eIF2α phosphorylation-activating transcription factor 4 (ATF4) axis is required for the expression of multiple transcription factors, including nuclear factor erythroid 2-related factor 2and its target genes responsible for mitochondrial homeostasis during ER stress. eIF2α phosphorylation-deficient (A/A) cells displayed dysregulated mitochondrial dynamics and mitochondrial DNA replication, decreased expression of oxidative phosphorylation complex proteins, and impaired mitochondrial functions during ER stress. ATF4 overexpression suppressed impairment of mitochondrial homeostasis in A/A cells during ER stress by promoting the expression of downstream transcription factors and their target genes. Our findings underscore the importance of the eIF2α phosphorylation-ATF4 axis for maintaining mitochondrial homeostasis through transcriptional reprogramming during ER stress.

Increase of histone acetylation by suberoylanilide hydroxamic acid enhances microspore reprogramming and expression of somatic embryogenesis transcription factors in Brassica napus.

In vivo, microspores in the anthers follow the gametophytic development pathway, culminating in the formation of pollen grains. Conversely, in vitro, under stress treatments, microspores can be reprogrammed into totipotent cells, initiating an embryogenic pathway that produces haploid and double-haploid embryos, which are important biotechnological tools in plant breeding. There is growing evidence that epigenetic reprogramming occurs during microspore embryogenesis through DNA methylation, but less is known about the role of histone modifications. This study investigates the dynamics of histone acetylation during the two microspore developmental pathways, microspore embryogenesis and pollen development, in Brassica napus. We analyzed histone H3 and H4 acetylation levels, histone acetyltransferase (HAT) activity and expression of HAC5 acetyltransferase using immunofluorescence, enzymatic activity assays, ELISA-like tests, and qPCR. Results showed a decrease in global histone acetylation levels during pollen maturation, correlated with reduced HAT activity and downregulation of the BnHAC5-like gene. In contrast, stress-induced microspore reprogramming led to increased histone acetylation levels, enhanced HAT activity, and upregulation of BnHAC5-like. Treatment with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor widely used in animal research but barely applied to plants, enhanced microspore embryogenesis initiation and proembryo formation, while increased histone acetylation levels. SAHA-treated proembryos showed higher expression than control of key embryogenesis transcription factors BnFUS3, BnAGL15, and BnLEC2, suggesting that histone hyperacetylation facilitates transcriptional activation of essential genes for somatic embryogenesis initiation. These findings provided new insights into the epigenetic regulation of this process and revealed new opportunities with histone epigenetic regulator inhibitors, to improve microspore embryogenesis induction for crop improvement.

Suppression of TGA2-Mediated Salicylic Acid Defence by Tomato Yellow Leaf Curl Virus C2 via Disruption of TCP7-Like Transcription Factor Activity in Tobacco.

Tomato yellow leaf curl virus (TYLCV) is a significant threat to tomato cultivation globally, transmitted exclusively by the whitefly Bemisia tabaci. While previous research suggests that the TYLCV C2 protein plays a role in fostering mutualistic interactions between the virus and its insect vectors, the specific mechanisms remain unclear. In this study, we show that the C2 protein interferes with the salicylic acid (SA) defence pathway by disrupting TCP7-like transcription factor-mediated regulation of TGA2 expression. Whitefly infestation increases the expression of TCP7-like transcription factors (TCP7-L1 and TCP7-L2), which subsequently trigger TGA2-dependent activation of BGL2 transcription, enhancing plant resistance to whiteflies. However, the TYLCV C2 protein interacts with these TCP7-like factors, reducing their binding affinity to the TGA2 promoter, which in turn suppresses BGL2 expression in the SA signalling pathway. These findings provide new insights into how TYLCV C2 modulates TCP7-like protein activity to impair SA-mediated defences, contributing to the mutualistic relationship between TYLCV and whiteflies. This work deepens our understanding of the complex regulatory networks underlying these virus-vector-host interactions.

Identification and functional characterization of the MYB transcription factor GmMYBLJ in soybean leaf senescence

Leaf senescence is an important agronomic trait that significantly influences the quality and yield of soybeans. v-Myb avian myeloblastosis viral oncogene homolog (MYB) transcription factors are considered crucial regulators governing leaf senescence, which can be utilized to improve agronomic traits in crops. However, our knowledge regarding the functional roles of soybean MYBs in leaf senescence is extremely limited. In this study, GmMYBLJ, a CCA1-like MYB, was identified and functionally characterized with respect to leaf senescence. The GmMYBLJ protein is localized in the nucleus, and a high accumulation of its transcripts was observed in nodules and embryos. Notably, GmMYBLJ was highly expressed in soybean senescent leaves and was transcriptionally induced by dark or NaCl treatment, as confirmed by histochemical GUS staining analysis. Ectopic overexpression of GmMYBLJ in Arabidopsis not only led to earlier leaf senescence, reduced chlorophyll content, and increased MDA accumulation but also promoted the expression of several WRKY family transcription factors and senescence-associated genes, such as SAG12 and ORE1. Further investigation showed that overexpression of GmMYBLJ accelerated Arabidopsis leaf senescence under darkness and in response to Pst DC3000 infection. Moreover, transgenic soybean plants overexpressing GmMYBLJ grew faster and exhibited accelerated senescence under salt stress. DAB staining analysis showed that GmMYBLJ induced ROS accumulation in soybean hairy roots and Arabidopsis leaves. Collectively, our results provided useful information into the functional roles of GmMYBLJ in both age-dependent and stress-induced senescence.

Iron Drives Eosinophil Differentiation in Allergic Airway Inflammation Through Mitochondrial Metabolic Adaptation.

Eosinophils play a crucial role as effector cells in asthma pathogenesis, with their differentiation being tightly regulated by metabolic mechanisms. While the involvement of iron in various cellular processes is well known, its specific role in eosinophil differentiation has largely remained unexplored. This study demonstrates that iron levels are increased during the differentiation process from eosinophil progenitorsto mature and activated eosinophils in the context of allergic airway inflammation. Through experiments involving iron chelators, supplements, and iron-deficient or iron-enriched diets, the indispensable role of iron in eosinophil lineage commitment both in vitro and in vivo is demonstrated. Remarkably, iron chelation effectively suppresses eosinophil differentiation and alleviates airway inflammation in a house dust mite(HDM)-induced mouse model of allergic asthma. Mechanistically, iron promotes the expression of transcription factors that enforce eosinophil differentiation, and maintains mitochondrial metabolic activities, leading to specific metabolic shifts within the tricarboxylic acid (TCA) cycle, with succinate promoting eosinophil differentiation. Overall, this study highlights the function of iron and underlying metabolic mechanisms in eosinophil differentiation, providing potential therapeutic strategies for asthma control.

SARS-CoV-2 Impairs Osteoblast Differentiation Through Spike Glycoprotein and Cytokine Dysregulation

Pulmonary and extrapulmonary manifestations have been reported following infection with SARS-CoV-2, the causative agent of COVID-19. The virus persists in multiple organs due to its tropism for various tissues, including the skeletal system. This study investigates the effects of SARS-CoV-2 infection, including both ancestral and Omicron viral strains, on differentiating mesenchymal stem cells (MSCs), the precursor cells, into osteoblasts. Although both viral strains can productively infect osteoblasts, precursor cell infection remained abortive. Viral exposure during osteoblast differentiation demonstrates that both variants inhibit mineral and organic matrix deposition. This is accompanied by reduced expression of runt-related transcription factor 2 (RUNX2) and increased levels of interleukin-6 (IL-6), a cytokine that negatively regulates osteoblast differentiation. Furthermore, the upregulation of receptor activator of nuclear factor kappa B ligand (RANKL) strongly suggests that the ancestral and Omicron variants may disrupt bone homeostasis by promoting osteoclast differentiation, ultimately leading to the formation of bone-resorbing cells. This process is dependent of spike glycoprotein since its neutralization significantly reduced the effect of infective SARS-CoV-2 and UV-C inactivated virus. This study underscores the capacity of ancestral and Omicron SARS-CoV-2 variants to disrupt osteoblast differentiation, a process essential for preserving the homeostasis and functionality of bone tissue.

Synthetic transcription factors establish the function of nine amino acid transactivation domains of Komagataella phaffii Mxr1.

The zinc finger transcription factor Mxr1 (methanol expression regulator 1) of the methylotrophic yeast Komagataella phaffii (formerly Pichia pastoris) harbors a DNA-binding domain (DBD) consisting of two C2H2 zinc fingers (Mxr1ZF) between amino acids 36-101 and a previously identified nine amino acid transactivation domain (9aaTAD) between residues 365-373 (TAD A, QELESSLNA). Beyond this, 21 putative 9aaTADs (designated TAD B-V) located between amino acids 401-1155 remain to be characterized. Here, we demonstrate that a compact synthetic transcription factor composed of Mxr1ZF and three tandem copies of TAD A can activate the transcription of Mxr1 target genes for ethanol and methanol metabolism with specificity and efficiency comparable to the full-length protein. Expression of individual synthetic transcription factors containing Mxr1ZF and each of the 20 putative 9aaTADs in K. phaffii Δmxr1 strain revealed that 10 of these putative TADs are functional, capable of reversing the growth defect of the mutant and activating transcription of target genes required for ethanol and methanol metabolism. Functional analysis indicates that Mxr1 9aaTADs rely on General Control Non-derepressible 5 (Gcn5), a histone acetyltransferase, for transactivation. These findings suggest that recruitment of Gcn5-mediated histone acetylation at target promoters is a critical step in transcriptional activation by Mxr1 9aaTADs. This study represents the first comprehensive characterization of 9aaTADs in a K. phaffii zinc finger transcription factor, providing insights into their mechanism and potential applications in synthetic biology.

GATA2 links stemness to chemotherapy resistance in acute myeloid leukemia.

Stemness-associated cell states are linked to chemotherapy resistance in AML. We uncovered a direct mechanistic link between expression of the stem cell transcription factor GATA2 and drug resistance. The GATA-binding protein 2 (GATA2) plays a central role in blood stem cell generation and maintenance. We find substantial intra- and inter-patient variability in GATA2 expression across AML patient samples. GATA2 expression varies by molecular subtype and has been linked to outcome. In a murine model, KMT2A-MLL3 driven AML originating from a stem cell or immature progenitor cell population have higher Gata2 expression and are more resistant to the standard AML chemotherapy agent doxorubicin. Deletion of Gata2 resulted in more robust induction of p53 following exposure to doxorubicin. ChIP-Seq, RNA-Seq and functional studies revealed that GATA2 regulates the expression of RASSF4, a modulator of the p53 inhibitor MDM2. GATA2 and RASSF4 are anti-correlated in human cell lines and AML patient cell bulk and single cell expression datasets. Knockdown of Rassf4 in Gata2 low cells resulted in doxorubicin or nutlin-3 resistance. Conversely, overexpression of Rassf4 results in sensitization of cells expressing high levels of Gata2. Finally, doxorubicin and nutlin-3 are synergistic in Gata2-high murine AML, as well as AML patient samples. We discovered a previously unappreciated role for GATA2 in dampening p53-mediated apoptosis via transcriptional regulation of RASSF4, a modulator of MDM2. This role for GATA2 directly links the expression of a stemness associated transcription factor to chemotherapy resistance.

P0106 Profiling inflammation-associated T helper subsets in Inflammatory Bowel Disease

Abstract Background Microbiota-specific CD4+ T cells drive chronic inflammation in Inflammatory Bowel Disease (IBD), comprising Crohn’s Disease (CD) and Ulcerative Colitis (UC). In previous projects we have identified several CD4+ T cell subsets enriched in the inflamed mucosa from naïve IBD patients, especially a colon-specific increase of HLA-DR+CD38+CD4+ memory T cells1. However, the functional properties remained to be elucidated. We therefore aimed to characterize CD4+ helper T cell lineage-specifying transcription factor (TF) expression and cytokine profiles in mucosa and circulation from IBD patients. Methods We collected intestinal samples and peripheral blood from patients and healthy controls undergoing diagnostic ileocolonoscopy, and subsequently employed 5-laser spectral flow cytometry to analyse single-cell data. Results For phenotypic characterization, a 37-antibody panel including TF and chemokine receptors was applied to 70 intestinal samples from 16 CD and 12 UC patients (including 22 non-inflamed, 22 inflamed samples and 16 samples in remission), as well as 5 healthy controls. Unbiased tSNE-based analysis revealed an increase of Foxp3+ Treg cells in inflamed biopsies. Particularly, in Ki-67+RORγt+ cells, we identified a cluster co-expressing Foxp3 and Helios, and a cluster expressed T-bet were enriched in inflamed colonic biopsies. As described before, two clusters of activated RORγt+HLA-DR+CD38+ T cell subset, one CD103+ and another CD103-, were increased in frequency in inflamed biopsies. Both clusters expressed CTLA-4, CD39 and Ki-67. In contrast, the frequencies of RORγt+ NKT-like cells (CD161+CD69+CD103-) were decreased in inflamed tissues. Next, we measured cytokine production in CD4+ T intestinal cells upon anti-CD3/CD28 stimulation of non-inflamed (healthy controls=8, IBD in active stage=8, IBD in remission=4) and inflamed samples (IBD in active stage=7). Frequencies of multifunctional CD103+ and CD103- CD154+ cells simultaneously producing IFNγ, TNFα and IL-2 were decreased in inflamed biopsies. On the contrary, CXCL-13 expression was elevated in the inflamed group. Conclusion In conclusion, we observed that a Th17/Treg and a Th17/Th1 subset were increased in inflamed biopsies, which we hypothesize to represent a transformation of Th17 to Treg or Th1. In addition, the HLA-DR+CD38+ subset displaying a Th17 profile was proliferating in inflamed mucosa, indicative of an active role in the disease pathogenesis. Simultaneously, Tregs were upregulated while CD4+ T cells produced less cytokines in inflamed mucosa, potentially indicating that Treg cells suppress the pro-inflammatory CD4+ T cell response in IBD patients. Thus, our results provide new clues about the functional contribution of CD4+ T cells to inflammation in IBD.

Single-cell transcriptome reveals three types of adipocytes associated with intramuscular fat content in pigs.

Intramuscular fat is an essential component of muscle tissue, and understanding its contribution to skeletal muscle fat infiltration and meat quality, together with the underlying genetic mechanisms, is a major topic in pig husbandry. However, the composition of cell types and gene expression profiles essential for this purpose remain largely unexplored. Here, we performed single-cell transcriptome analysis on muscle tissue from adult pigs and identified 15 cell types, including three previously uncharacterized types of adipocytes: Adipocyte 1, Adipocyte 2, and Aregs. Phenotypic analysis showed their proportions correlated closely with intramuscular fat content. Based on integrated analysis of ATAC-seq with RNA-seq data, Adipocyte 1 and Aregs have gene expression profiles and transcription factor (TF) motif enrichment typical of adipocytes. On the other hand, myogenic TF motifs were enriched in marker gene promoters in Adipocyte 2, suggesting that these cells originate from muscle cells. Moreover, the marker gene promoters and lineage-specific TF expression in these three adipocyte types were conserved between pigs and humans. These findings provide deep insights towards understanding the complexity of mammalian intramuscular adipocyte types and the gene regulation underlying their organization and function.

Insight into the anti-allergic impacts of fucoidan from Gracilaria lemaneiformis in mitigating allergic reactions induced by shrimp tropomyosin via regulating Th1/Th2 cytokines and T cell subsets.

Fucoidan is a natural sulfated polysaccharide with immunoregulatory function. In this work, the anti-allergic impacts of Gracilaria lemaneiformis fucoidan (GLF) in mitigating allergic reactions induced by shrimp tropomyosin were investigated. As the results, GLF performed significant hyaluronidase inhibition ability (IC50 = 0.272 mg/mL), alleviated the allergic reactions of RAW 264.7 macrophage cells via decreasing the secretion of TNF-α and NO by 58.75 % and 46.17 %, respectively, and mitigated the degranulation degree and secretion of IL-4, TNF-α and histamine as well as promoted IL-10 secretion in RBL-2H3 mast cells. In BALB/c mouse, after gavage of GLF, the mouse allergic symptoms got significantly alleviated, the secretion of IgE and IgG1 got reduced, IgG2a got promoted, the IL-4 secretion from mouse spleen lymphocytes (SLP) significantly declined, and IL-10 and IFN-γ secretion in SLP got improved, which indicated GLF performed significantly anti-allergic functions via transforming Th2 response into Th1 and Treg response. Moreover, the SLP cells treated by GLF had lower expression of GATA-3, higher T-bet and Foxp3 expression, which indicated GLF could mitigate allergic reactions via regulating T-bet, GATA3 and Foxp3 transcription factor expression of T cell subsets. Therefore, GLF could serve as anti-allergic substances for shrimp-induced allergy via regulating Th1/Th2 cytokines and T cell subsets.

Apoptosis antagonizing transcription factor expression and its validation as a potential diagnostic and prognostic biomarker in oral squamous cell carcinoma

BackgroundOral squamous cell carcinoma (OSCC) is characterized by a high degree of malignancy and poor prognosis. This study aimed to investigate the expression of apoptosis antagonizing transcription factor (AATF) in OSCC, examine its correlation with clinicopathological features, assess its prognostic implications, and explore its potential role in OSCC progression.MethodsExpression profiles and clinical data of OSCC patients were obtained from The Cancer Genome Atlas (TCGA). Immunohistochemical analysis on tissue microarrays was performed to assess AATF expression in OSCC. Functional enrichment analyses were conducted to identify potential signaling pathways and biological functions associated with AATF. Logistic regression analyses were employed to evaluate the relationship between AATF expression and clinicopathological features. Immune cell infiltration was assessed using single-sample gene set enrichment analysis (ssGSEA). The prognostic value of AATF was determined using Kaplan-Meier and Cox regression analyses. A nomogram was developed to predict overall survival (OS) rates at one, three-, and five years post-cancer diagnosis. Validation of AATF expression was performed using quantitative real-time PCR (qRT-PCR)ResultsAATF was significantly overexpressed in OSCC, and high AATF expression correlated with adverse clinicopathological features, including histologic grade and lymph node metastasis. Functional enrichment analysis revealed several enriched pathways, including epidermis development, immunoglobulin complex, antigen binding and IL-17 signaling pathway. Notably, AATF overexpression was negatively correlated with the infiltration levels of mast cells, interdigitating dendritic cells and Th 17 cells. High AATF expression significantly predicted poorer overall survival (OS) and disease-specific survival (DSS). Multivariate Cox analysis confirmed AATF as an independent negative prognostic marker of OS. Validation via qRT-PCR confirmed the overexpression of AATF in OSCC tissues.ConclusionElevated expression of AATF in OSCC correlates with adverse clinicopathological features and negatively impacts immune cell infiltration. High AATF levels serve as an independent marker of poor OS and DSS. These findings support AATF as a valuable prognostic biomarker and a potential therapeutic target in OSCC, warranting further investigation.

The expression of transcription factors in the human fetal subthalamic nucleus suggests its origin from the first hypothalamic prosomere.

In this study, we analyzed the spatio-temporal pattern of expression of specific transcription factors (PITX2, FOXA1, BARHL1, FOXP1, FOXP2) in the human fetal subthalamic nucleus and its neighboring structures from 11 postconceptional weeks (PCW) to 3 postnatal months. We found that all analyzed transcription factors are expressed already during the early fetal period (at 11 PCW). Both FOXP1- and FOXP2-immunoreactive cells were found in the subthalamic nucleus as well as in the striatum, thalamus, reticular nucleus, but not in the zona incerta. FOXP2-ir cells were also found in the lateral hypothalamic-supramamillary area (LHA-SMA) and internal pallidal segment.On the other hand, PITX2, FOXA1 and BARHL1 were expressed exclusively in the subthalamic nucleus and LHA-SMA, from 11 PCW until the birth, the only exception being gradual loss of BARHL1 expression in the LHA-SMA during the late fetal period.Our findings present the first evidence in the human fetal brain that neurons of the subthalamic nucleus do not originate in the diencephalon, as was proposed by classical histological studies, but instead share a common hypothalamic (hp1 prosomere) origin with neurons of the LHA-SMA group, as proposed by the prosomeric model of brain development.

ICE1 (Inducer of CBF Expression 1) Is Essential for the Jasmonate-Regulated Development of Stamen in Arabidopsis thaliana.

Floral organ development, pollen germination and pollen tube growth are crucial for plant sexual reproduction. Phytohormones maintain these processes by regulating the expression and activity of various transcription factors. ICE1, a MYC-like bHLH transcription factor, has been revealed to be involved in cold acclimatisation of Arabidopsis. This study shows that ICE1 regulates multiple aspects of sexual reproduction, including stamen development, pollen development and germination. Loss-of-function mutants of ICE1 exhibit floral organs with shorter filaments, defective anther dehiscence and lower pollen viability compared to the wild type. These abnormalities result in disrupted fertilisation, leading to short siliques, a high rate of seed abortion, and dark, shriveled mature seeds. JAZ proteins (JAZ1 and JAZ9) interact with ICE1, inhibiting its transcriptional activity on jasmonic acid (JA)-responsive genes, including MYB21, MYB24 and MYB108. This study highlights the essential role of ICE1 as a signalling agent in the JA-regulated maintenance of sexual reproduction in Arabidopsis thaliana.

Genome-Wide Identification and Expression Analysis of bHLH-MYC Family Genes from Mustard That May Be Important in Trichome Formation.

The trichomes of mustard leaves have significance due to their ability to combat unfavorable external conditions and enhance disease resistance. It was demonstrated that the MYB-bHLH-WD40 (MBW) ternary complex consists of MYB, basic Helix-Loop-Helix (bHLH), and WD40-repeat (WD40) family proteins and plays a key role in regulating trichome formation and density. The bHLH gene family, particularly the Myelocytomatosis (MYC) proteins that possess the structural bHLH domain (termed bHLH-MYC), are crucial to the formation and development of leaf trichomes in plants. bHLH constitutes one of the largest families of transcription factors in eukaryotes, of which MYC is a subfamily member. However, studies on bHLH-MYC transcription factors in mustard have yet to be reported. In this study, a total of 45 bHLH-MYC transcription factors were identified within the Brassica juncea genome, and a comprehensive series of bioinformatic analyses were conducted on their structures and properties: an examination of protein physicochemical properties, an exploration of conserved structural domains, an assessment of chromosomal positional distributions, an analysis of the conserved motifs, an evaluation of the gene structures, microsynteny analyses, three-dimensional structure prediction, and an analysis of sequence signatures. Finally, transcriptome analyses and a subcellular localization examination were performed. The results revealed that these transcription factors were unevenly distributed across 18 chromosomes, showing relatively consistent conserved motifs and gene structures and high homology. The final results of the transcriptome analysis and gene annotation showed a high degree of variability in the expression of bHLH-MYC transcription factors. Five genes that may be associated with trichome development (BjuVA09G22490, BjuVA09G13750, BjuVB04G14560, BjuVA05G24810, and BjuVA06G44820) were identified. The subcellular localization results indicated that the transcription and translation products of these five genes were expressed in the same organelle: the nucleus. This finding provides a basis for elucidating the roles of bHLH-MYC family members in plant growth and development, and the molecular mechanisms underlying trichome development in mustard leaves.

The role of OCT4 and CD44 in lower lip carcinogenesis.

Carcinogenesis is characterized by the transformation of normal cells into malignant cells. Concerning the lower lip, exposure to UV radiation is the main etiological factor associated with the development of epidermoid carcinomas and actinic cheilitis. According to the hierarchical model theory, cancer development is driven by populations of cancer stem cells. In this context, this study aimed to compare the expression of octamer-binding transcription factor 4 (OCT4) and CD44 in 40 lower lip epidermoid carcinoma (LLEC) and 40 actinic cheilitis (AC) cases. OCT4 and CD44 expressions were assessed semi-quantitatively according to the percentage of positive epithelial cells (PP) and intensity of expression (IE), resulting in a total immunolabeling score (PIT). No statistically significant differences were detected between OCT4 and CD44 immunoexpression and clinicopathological parameters, except for lymph node metastasis, in which a decrease in CD44 expression in the core tumor of cases with lymph node metastasis was observed. Furthermore, decreased CD44 expression was observed in LLEC cases when compared to AC cases. The findings reported herein suggest a higher participation of CD44 in early carcinogenesis stages. In addition, the imbalance between OCT4 and CD44 immunoexpressions suggests the presence of different neoplastic cell subpopulations.

Altered Expression of Epigenetic and Transcriptional Regulators in ERβ Knockout Rat Ovaries During Postnatal Development.

We analyzed the transcriptome data of wildtype and estrogen receptor β knockout (ErβKO) rat ovaries during the early postnatal period and detected remarkable changes in epigenetic regulators and transcription factors. Compared with postnatal day (PD) 4.5 ovaries, PD 6.5 wildtype ovaries possessed 581 differentially expressed downstream transcripts (DEDTs), including 17 differentially expressed epigenetic regulators (DEERs) and 23 differentially expressed transcription factors (DETFs). Subsequently, compared with PD 6.5 ovaries, PD 8.5 wildtype ovaries showed 920 DEDTs, including 24 DEERs and 68 DETFs. The DEDTs, DEERs, and DETFs in wildtype ovaries represented the gene expression during primordial follicle activation and the gradual development of primary follicles of first-wave origin because the second-wave follicles remained dormant during this developmental period. When we compared the transcriptome data of age-matched ErβKO ovaries, we observed that PD 6.5 ErβKO ovaries had 744 DEDTs compared with PD 4.5 ovaries, including 46 DEERs and 55 DETFs. The loss of ERβ rapidly activated the primordial follicles of both first- and second-wave origin on PD 6.5 and showed a remarkable increase in DEDTs (744 vs. 581). However, compared with PD 6.5 ovaries, PD 8.5 ErβKO ovaries showed only 191 DEDTs, including 8 DEERs and 10 DETFs. This finding suggests that the PD 8.5 ErβKO ovaries did not undergo remarkable ovarian follicle activation greater than that had already occurred in PD 6.5 ErβKO ovaries. The results also showed that the numbers of DEERs and DETFs were associated with increased changes in DEDTs; the greater the number of DEERs or DETFs, the larger the number of DEDTs. In addition to the quantitative differences in DEERs and DETFs between the wildtype and ErβKO ovaries, the differentially expressed regulators showed distinct patterns. We identified that 17 transcripts were tied to follicle assembly, 6 to follicle activation, and 12 to steroidogenesis. Our observations indicate that a loss of ERβ dysregulates the epigenetic regulators and transcription factors in ErβKO ovaries, which disrupts the downstream genes in ovarian follicles and increases follicle activation. Further studies are required to clarify if ERβ directly or indirectly regulates DEDTs, including DEERs and DETFs, during the neonatal development of rat ovarian follicles.

Nitrogen availability modulates carotene biosynthesis, chromoplast biogenesis, and cell wall composition in carrot callus.

Carrot callus grown on a medium with increased nitrogen have reduced carotenoid accumulation, changed gene expression, high amount of vesicular plastids and altered cell wall composition. Carotenoid biosynthesis is vital for plant development and quality, yet its regulation under varying nutrient conditions remains unclear. To explore the effects of nitrogen (N) availability, we used carrot (Daucus carota L.) model callus cultures in vitro as a controlled system for studying nutrient-regulated metabolic processes. Two mineral media differing in N content and NO₃⁻/NH₄⁺ ratios were used. Comprehensive analyses, HPLC, transmission electron microscopy, immunochemistry, and RNA sequencing, revealed notable cellular and molecular responses to N treatments. The results demonstrated that N supplementation reduced carotenoid content by 50%, particularly β-carotene and α-carotene. The composition of chromoplast types shifted, with vesicular chromoplasts dominating (55%), followed by a globular type (23%), while in the control callus, globular and crystalline types predominated (57% and 33%, respectively). Immunohistochemistry showed increased presence of high-esterified pectins and arabinogalactan proteins in N-treated cells. Transcriptomic analysis identified 1704 differentially expressed genes (DEGs), including only two in the carotenoid biosynthesis pathway: phytoene synthase 2 (PSY2) and zeaxanthin epoxidase (ZEP). PSY2, which encodes the carotenoid rate-limiting enzyme, showed expression levels that corresponded with reduced carotene content. Other DEGs included 15 involved in nitrogen transport, 1 in nitrogen assimilation, 40 in cell wall biosynthesis and modification, and 9 in phenylpropanoid/flavonoid pathways. N-treated callus exhibited altered expression of MADS-box, NLP, bZIP, and ethylene-responsive transcription factors. These findings reveal how nitrogen availability disrupts carotenoid biosynthesis and triggers extensive chromoplast and cell wall remodeling, providing a cellular framework for understanding nutrient-regulated metabolic shifts.

Regulation of eumelanogenesis-related genes by ethanol extract of Melaleuca Leucadendron leaves.

Eumelanin, a type of skin melanin pigment, possesses the ability to absorb a wide range of wavelengths, providing protection to the skin from ultraviolet radiation. However, excessive production of eumelanin may result in hyperpigmentation. Consequently, the development of skin-brightening products that suppress eumelanin synthesis to achieve a lighter and more even skin tone is necessary. The present study investigated the potential application of Melaleuca leucadendron as a natural skin-brightening agent. We investigated the effects of the ethanol leaf extract of M. Leucadendron on α-melanocyte-stimulating hormone-induced melanogenesis in B16F10 cells and identified the key factors involved in melanogenesis. This leaf extract significantly inhibited melanin production by downregulating the expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein 1, and dopachrome tautomerase without causing cytotoxicity. Furthermore, it substantially reduced melanin content in a 3D skin model. These results suggest that the extract of M. Leucadendron is a promising, safe, and effective skin-brightening agent.