Evolutionarily Conserved Research Articles

Establishing a dominant early larval sex-selection strain in the Asian malaria vector Anopheles stephensi

BackgroundGenetic biocontrol interventions targeting mosquito-borne diseases require the release of male mosquitoes exclusively, as only females consume blood and transmit pathogens. Releasing only males eliminates the risk of increasing mosquito bites and spreading pathogens while enabling effective population control. The aim of this study is to develop robust sex-sorting methods for early larval stages in mosquitoes, enabling scalable male-only releases for genetic biocontrol interventions.MethodsTo address the challenge of sex-sorting in the Asian malaria vector Anopheles stephensi, we engineer Sexing Element Produced by Alternative RNA-splicing of a Transgenic Observable Reporter (SEPARATOR). This dominant fluorescent-based method, previously proven effective in Aedes aegypti, exploits sex-specific alternative splicing of a reporter to ensure exclusive male-specific expression early in development. The sex-specific alternative RNA splicing of the doublesex gene was selected as a target for engineering SEPARATOR due to its evolutionary conservation in insects. To expand SEPARATOR’s applicability for genetic sexing, we assessed the cross-species sex-specific RNA splicing activity of the An. gambiae doublesex (AngDsx) splicing module in An. stephensi. Male-specific enhanced green fluorescent protein (EGFP) expression was verified throughout the mosquito life cycle using a fluorescent stereomicroscope.ResultsOur results confirm that SEPARATOR regulates male-specific EGFP expression in An. stephensi and enables reliable positive male selection from the first instar larval stages. Molecular analysis demonstrates that male-specific EGFP expression is dependent on doublesex sex-specific splicing events. Additionally, the splicing module from An. gambiae operates effectively in An. stephensi, demonstrating evolutionary conservation in sex-specific splicing events between these species.ConclusionsSEPARATOR’s independence from sex-chromosome linkage provides resistance to breakage that could be mediated by meiotic recombination and chromosomal rearrangements, making it highly suitable for mass male releases. By enabling precise male selection from the first instar larval stages, SEPARATOR represents a significant advancement that will aid in the genetic biocontrol for Anopheles mosquitoes.Graphical

The uncharacterized protein ZNF200 interacts with PRMT3 and aids its stability and nuclear translocation

Protein arginine methyltransferase 3 (PRMT3), a type I arginine methyltransferase is localized predominantly in the cytoplasm and regulates different cellular functions. Nevertheless, PRMT3 also exhibits regulatory functions in the nucleus by interacting with the liver X receptor alpha (LXRα) and catalyzes asymmetric dimethylation modifications at arginine 3 of histone 4 (H4R3me2a). However, very little is known about the regulation of the versatile global regulator PRMT3 and how PRMT3 is translocated to the nucleus. In this study, we identified ZNF200, a hitherto uncharacterized protein, as a potential binding partner of PRMT3 through yeast two-hybrid screening. We confirmed the interaction of PRMT3 with ZNF200 using immunoprecipitation and in vitro pull-down experiments. GST pull-down experiments and molecular docking studies revealed that the N-terminal zinc finger domain of PRMT3 binds to the C-terminal zinc finger regions of ZNF200. Furthermore, the evolutionary conservation of the Znf domain of PRMT3 correlates with the emergence of ZNF200 in mammals. We found that ZNF200 stabilizes PRMT3 by inhibiting its proteasomal degradation. ZNF200, a nuclear-predominant protein, promotes the nuclear translocation of PRMT3, leading to the global increase of H4R3me2a modifications. These findings imply that ZNF200 is a critical regulator of the steady-state levels and nuclear and epigenetic functions of PRMT3.

Characterization of single-cell cis-regulatory elements informs implications for cell differentiation.

Cis-regulatory elements (CREs) govern the specific patterns and dynamics of gene expression in cells during development, which are the fundamental mechanisms behind cell differentiation. However, the genomic characteristics of single-cell CREs (scCREs) closely linked to cell differentiation during development remain unclear. To explore this, we systematically analyzed ∼250,000 putative scCREs obtained from snATAC-seq analysis of the developing mouse cerebellum. We found that over 80% of these scCREs show pleiotropic effects, being active in two or more cell types. The pleiotropic degrees of proximal and distal scCREs are positively correlated with the density and diversity of transcription factor (TF) binding motifs and GC content. There is a negative correlation between the pleiotropic degrees of scCREs and their distances to the nearest TSSs, and proximal scCREs display higher relevance strengths than distal ones. Furthermore, both proximal and distal scCREs related to cell differentiation exhibit enhanced sequence-level evolutionary conservation, increased density and diversity of TF binding motifs, elevated GC content, and greater distances from their nearest genes. Together, our findings reveal the general genomic characteristics of putative scCREs and provide insights into the genomic and evolutionary mechanisms by which scCREs regulate cell differentiation during development.

Microprotein-encoding RNA regulation in cells treated with pro-inflammatory and pro-fibrotic stimuli

BackgroundRecent analysis of the human proteome via proteogenomics and ribosome profiling of the transcriptome revealed the existence of thousands of previously unannotated microprotein-coding small open reading frames (smORFs). Most functional microproteins were chosen for characterization because of their evolutionary conservation. However, one example of a non-conserved immunomodulatory microprotein in mice suggests that strict sequence conservation misses some intriguing microproteins.ResultsWe examine the ability of gene regulation to identify human microproteins with potential roles in inflammation or fibrosis of the intestine. To do this, we collected ribosome profiling data of intestinal cell lines and peripheral blood mononuclear cells and used gene expression of microprotein-encoding transcripts to identify strongly regulated microproteins, including several examples of microproteins that are only conserved with primates.ConclusionThis approach reveals a number of new microproteins worthy of additional functional characterization and provides a dataset that can be queried in different ways to find additional gut microproteins of interest.

Drosophila Toxicogenomics: genetic variation and sexual dimorphism in susceptibility to 4-Methylimidazole

Background4-methylimidazole is a ubiquitous and potentially carcinogenic environmental toxicant. Genetic factors that contribute to variation in susceptibility to its toxic effects are challenging to assess in human populations. We used the Drosophila melanogaster Genetic Reference Panel (DGRP), a living library of natural genetic variation, to identify genes with human orthologs associated with variation in susceptibility to 4-methylimidazole.ResultsWe screened 204 DGRP lines for survival following 24-hour exposure to 4-methylimidazole. We found extensive genetic variation for survival, with a broad sense heritability of 0.82; as well as genetic variation in sexual dimorphism, with a cross-sex genetic correlation of 0.59. Genome-wide association analyses identified a total of 241 candidate molecular polymorphisms in or near 273 unique genes associated with survival. These polymorphisms had either sex-specific or sex-antagonistic effects, and most had putative regulatory effects. We generated interaction networks using these candidate genes as inputs and computationally recruited genes with known physical or genetic interactions. The network genes were significantly over-represented for gene ontology terms involving all aspects of development (including nervous system development) and cellular and organismal functions as well as canonical signaling pathways, and most had human orthologs.ConclusionsThe genetic basis of variation in sensitivity to acute exposure to 4-methylimidazole in Drosophila is attributable to variation in genes and networks of genes known for their effects on multiple developmental and cellular processes, including possible neurotoxicity. Given evolutionary conservation of the underlying genes and pathways, these insights may be applicable to humans.

Origin, Evolution, and Diversification of the Expansin Family in Plants

The cell wall is a crucial feature that allows ancestral streptophyte green algae to colonize land. Expansin, an extracellular protein that mediates cell wall loosening in a pH-dependent manner, could be a powerful tool for studying cell wall evolution. However, the evolutionary trajectory of the expansin family remains largely unknown. Here, we conducted a comprehensive identification of 2461 expansins across 64 sequenced species, ranging from aquatic algae to terrestrial plants. Expansins originated in chlorophyte algae and may have conferred the ability to loosen cell walls. The four expansin subfamilies originated independently: α-expansin appeared first, followed by β-expansin, and then expansin-like A and expansin-like B, reflecting the evolutionary complexity of plant expansins. Whole genome duplication/segmental duplication and tandem duplication events greatly contributed to expanding the expansin family. Despite notable changes in sequence characteristics, the intron distribution pattern remained relatively conserved among different subfamilies. Phylogenetic analysis divided all the expansins into five clades, with genes from the same subfamily tending to cluster together. Transcriptome data from 16 species across ten lineages and qRT-PCR analysis revealed varying expression patterns of expansin genes, suggesting functional conservation and diversification during evolution. This study enhances our understanding of the evolutionary conservation and dynamics of the expansin family in plants, providing insight into their roles as cell wall-loosening factors.

Desert landscape features influencing the microgeographic genetic structure of Nelson's pocket mouse Chaetodipus nelsoni.

Elucidating the factors that drive the genetic patterns of natural populations is key in evolutionary biology, ecology and conservation. Hence, it is crucial to understand the role that environmental features play in species genetic diversity and structure. Landscape genetics measures functional connectivity and evaluates the effects of landscape composition, configuration, and heterogeneity on microevolutionary processes. Deserts constitute one of the world's most widespread biomes and exhibit a striking heterogeneity of microhabitats, yet few landscape genetics studies have been performed with rodents in deserts. We evaluated the relationship between landscape and functional connectivity, at a microgeographic scale, of the Nelson's pocket mouse Chaetodipus nelsoni in the Mapimí Biosphere Reserve (Chihuahuan desert). We used single-nucleotide polymorphisms and characterized the landscape based on on-site environmental data and from Landsat satellite images. We identified two distinct genetic clusters shaped by elevation, vegetation and soil. High elevation group showed higher connectivity in the elevated zones (1250-1350 m), with scarce vegetation and predominantly rocky soils; whereas that of Low elevation group was at <1200 m, with denser vegetation and sandy soils. These genetic patterns are likely associated with the species' locomotion type, feeding strategy and building of burrows. Interestingly, we also identified morphological differences, where hind foot size was significantly smaller in individuals from High elevation compared to Low elevation, suggesting the possibility of ecomorphs associated with habitat differences and potential local adaptation processes, which should be explored further. These findings improve our understanding of the genetics and ecology of C. nelsoni and other desert rodents.

Deciphering the conformational changes induced by high-risk nsSNPs in β-lactoglobulin

Whey protein from bovine milk is highly valued in the food and pharmaceutical industries because of its high protein content and abundance of essential amino acids. The relationship between whey protein and the β-lactoglobulin (BLG) gene has been extensively discussed because BLG is the most abundant whey protein, making up approximately 50 % of the total whey protein in bovine milk. In recent years, researchers have been interested in this gene because of its critical role in healthy milk production, and any genetic polymorphism in this gene may deteriorate the milk quality. In the current study, we identified several deleterious and damaging non-synonymous single nucleotide polymorphisms (nsSNPs) in BLG and analyzed their destabilizing effects using different computational algorithms. Cumulative results from all tools and evolutionary conservation profiles of BLG suggested that four nsSNPs, G17A, W19C, F136S, and C119R, were the most deleterious and could affect the structural integrity of the protein. Detailed molecular dynamics simulation analysis revealed that all variants induced major structural alterations, that affected the ability of the protein to interact with natural and synthetic ligands. Particularly, the G17A, F136S, and C119R variants induced large conformational changes in the EF loop and main α-helix of BLG, which may affect the access of natural and synthetic ligands to the central calyx of BLG. We hope that the suggested nsSNPs will guide future studies and assist researchers in improving the quality of bovine milk.

Conservative character of the germ-line cyst organization within enchytraeids (Annelida: Clitellata) ovary – new proofs based on two Achaeta species

Ovaries in a minute and mainly aquatic clitellates, collectively termed microdriles, are usually tiny paired gonads localized, depending on the family/subfamily, in segments VI, XI, XII, or XIII. Sometimes, two pairs of ovaries are present in consecutive segments, or ovaries are unpaired. Usually, accumulating yolk (vitellogenic) oocytes detach from ovaries and float in the coelom cavity.This study presents the microscopical analyses of unpaired ovaries found in two representatives of the genus Achaeta (family Enchytraeidae). The ovary is an inconspicuous organ composed of germ-line cysts uniting early meiotic cells. Cysts comprise 16 synchronously developing cells interconnected via cytoplasmic bridges to the central cytoplasmic mass, termed cytophore. Each interconnected cell has one bridge connecting it to the cytophore. Clustering germ cells are enveloped by elongated somatic cells. The developmental synchrony within cysts is lost when one cell per cyst forms prominent microvilli, gather vast amounts of nutrients (yolk), and becomes an oocyte. The remaining 15 cells do not form microvilli, grow slowly, and are regarded as nurse cells that supply the oocyte with organelles and probably macromolecules. Such cysts detach from the ovary and float freely in the segmental cavity. Nurse cells and vitellogenic oocyte are still connected to the ball-like cytophore. Vitellogenic oocytes gather vast amounts of reserve material, mainly protein spheres. Finally, oocytes lose contact with the cytophore, and nurse cells no longer accompany them.The ovary organization and oogenesis scenario observed in this study are broadly similar to that described for other enchytraeid species, such as Enchytraeus albidus and Grania postclitellochaeta, and have been classified as the “Enchytraeus” type of ovary. The obtained results show that despite the unpaired nature of the Achaeta ovary and some differences in ovary morphology and oogenesis between different enchytraeid taxa, the ovaries of these clitellates are consistently composed of 16-celled germ-line cysts equipped with cytophore. Moreover, the presence of cysts equipped with cytophore in the ovaries of the studied Achaeta specimens provides the subsequent evidence that the formation of such germ-line cysts is a conserved aspect of oogenesis within the Clitellata. This consistency in the ovarian and oogenic patterns underscores the evolutionary conservation of these reproductive traits within the Enchytraeidae and clitellate annelids.

Revealing missing protein-ligand interactions using AlphaFold predictions

Protein–ligand interactions represent an essential step to understand the bases of molecular recognition, an intense field of research in many scientific areas. Structural biology has played a central role in unveiling protein-ligand interactions, but current techniques are still not able to reliably describe the interactions of ligands with highly flexible regions. In this work, we explored the capacity of AlphaFold2 (AF2) to estimate the presence of interactions between ligands and residues belonging to disordered regions. As these interactions are missing in the crystallographic-derived structures, we called them “ghost interactions”. Using a set of protein structures experimentally obtained after AF2 was trained, we found that the obtained models are good predictors of regions associated with order-disorder transitions. Additionally, we found that AF2 predicts residues making ghost interactions with ligands, which are mostly buried and show differential evolutionary conservation with the rest of the residues located in the flexible region. Our findings could fuel current areas of research that consider, given their biological relevance and their involvement in diseases, intrinsically disordered proteins as potentially valuable targets for drug development.

Transcriptomic and bioinformatic analysis of Histone H2A-genes in Lates calcarifer and Oreochromis niloticus upon Vibrio vulnificus challenge

Histone H2A-derived antimicrobial peptides (AMPs) have been recognized for their antimicrobial properties and role in host defense mechanisms. The present study investigated the transcriptional responses of two histone H2A-derived AMPs, Lc-Histone from Lates calcarifer and GIFT-Histone from Oreochromis niloticus, in response to Vibrio vulnificus infection. The genes encoding these peptides were amplified and sequenced from fingerling stage fishes, followed by in silico analysis and phylogenetic characterization using ClustalW. Computational methods were used to assess their functional attributes, and in vivo bacterial challenge assay was employed to evaluate the efficacy. Sequence alignment identified conserved histone motifs, supporting their evolutionary conservation. The antimicrobial peptide database predicted membrane interaction potential, suggesting antimicrobial activity, alongside biofilm-active properties and efficient expression in heterologous protein systems. Expression profiling of Histone H2A-derived AMP genes under Gram-negative bacterial stimulation revealed distinct temporal dynamics, indicative of their innate immune response involvement. Significant gene expression variations were observed between L. calcarifer and O. niloticus. These baseline findings enhance understanding of host defense mechanisms and bacterial interactions in aquaculture. The antimicrobial potential of histone H2A-derived AMPs highlights their significance as therapeutic agents and warrants further investigation into their mechanisms of action and optimal usage in aquaculture settings.

Structural basis for molecular assembly of fucoxanthin chlorophyll a/c-binding proteins in a diatom photosystem I supercomplex

Photosynthetic organisms exhibit remarkable diversity in their light-harvesting complexes (LHCs). LHCs are associated with photosystem I (PSI), forming a PSI-LHCI supercomplex. The number of LHCI subunits, along with their protein sequences and pigment compositions, has been found to differ greatly among the PSI-LHCI structures. However, the mechanisms by which LHCIs recognize their specific binding sites within the PSI core remain unclear. In this study, we determined the cryo-electron microscopy structure of a PSI supercomplex incorporating fucoxanthin chlorophyll a/c-binding proteins (FCPs), designated as PSI-FCPI, isolated from the diatom Thalassiosira pseudonana CCMP1335. Structural analysis of PSI-FCPI revealed five FCPI subunits associated with a PSI monomer; these subunits were identified as RedCAP, Lhcr3, Lhcq10, Lhcf10, and Lhcq8. Through structural and sequence analyses, we identified specific protein–protein interactions at the interfaces between FCPI and PSI subunits, as well as among FCPI subunits themselves. Comparative structural analyses of PSI-FCPI supercomplexes, combined with phylogenetic analysis of FCPs from T. pseudonana and the diatom Chaetoceros gracilis, underscore the evolutionary conservation of protein motifs crucial for the selective binding of individual FCPI subunits. These findings provide significant insights into the molecular mechanisms underlying the assembly and selective binding of FCPIs in diatoms.

Structural basis for molecular assembly of fucoxanthin chlorophyll a/c-binding proteins in a diatom photosystem I supercomplex.

Photosynthetic organisms exhibit remarkable diversity in their light-harvesting complexes (LHCs). LHCs are associated with photosystem I (PSI), forming a PSI-LHCI supercomplex. The number of LHCI subunits, along with their protein sequences and pigment compositions, has been found to differ greatly among the PSI-LHCI structures. However, the mechanisms by which LHCIs recognize their specific binding sites within the PSI core remain unclear. In this study, we determined the cryo-electron microscopy structure of a PSI supercomplex incorporating fucoxanthin chlorophyll a/c-binding proteins (FCPs), designated as PSI-FCPI, isolated from the diatom Thalassiosira pseudonana CCMP1335. Structural analysis of PSI-FCPI revealed five FCPI subunits associated with a PSI monomer; these subunits were identified as RedCAP, Lhcr3, Lhcq10, Lhcf10, and Lhcq8. Through structural and sequence analyses, we identified specific protein-protein interactions at the interfaces between FCPI and PSI subunits, as well as among FCPI subunits themselves. Comparative structural analyses of PSI-FCPI supercomplexes, combined with phylogenetic analysis of FCPs from T. pseudonana and the diatom Chaetoceros gracilis, underscore the evolutionary conservation of protein motifs crucial for the selective binding of individual FCPI subunits. These findings provide significant insights into the molecular mechanisms underlying the assembly and selective binding of FCPIs in diatoms.

Orchestrating ROS regulation: coordinated post-translational modification switches in NADPH oxidases.

Reactive oxygen species (ROS) are among the most important signaling molecules, playing a significant role in plant growth, development, and responses to various environmental stresses. Respiratory burst oxidase homologs (RBOHs) are key enzymes in ROS production. Plants tightly regulate the activation and deactivation of RBOHs through various post-translational modifications (PTMs), including phosphorylation, ubiquitination, S-nitrosylation, and persulfidation. These PTMs fine-tune ROS production, ensuring normal plant growth and development while facilitating rapid responses to abiotic and biotic stresses. This review discusses the effects of different PTMs on RBOH function and their biological relevance. Additionally, we examine the evolutionary conservation of PTM sites and emphasize the complex interplay between multiple PTMs regulating RBOHs.

Exploring influential factors on biomass and diversity of ancient trees in human-dominated regions: A case study in Guangdong Province, China

Ancient trees, which are vital for biodiversity and cultural heritage, maintain species richness, ecosystem resilience, and societal interconnectedness. However, escalating global climate change and human activities have led to widespread declines in ancient tree diversity and habitat degradation. Hence, understanding ancient tree dynamics is vital for precise conservation strategies, fostering harmony between society and ecology. This study addresses the gap in understanding the factors influencing ancient tree biomass and diversity in human-dominated areas. This study first collected biomass equations for ancient tree species. The biomass of ancient trees within human-influenced regions of Guangdong Province was subsequently computed in detail. Finally, by employing a structural equation model, we sought to quantitatively elucidate the influence of natural variables (encompassing geography, topography, soil composition, and climatic conditions) alongside anthropogenic variables (including population density, per capita GDP, the human footprint, ancient villages, and religious sites) on both the biomass and species richness of ancient trees. The species with the highest total biomass included Ficus microcarpa L.f. (2.45 × 105 t), Ficus concinna (Miq.) Miq. (4.07 × 104 t), and Litchi chinensis Sonn. (3.16 × 104 t). Moreover, the biomass presented a pronounced phylogenetic signal and evolutionary conservation. According to the results of the structural equation model, across the entire study area, soil characteristics emerged as the most influential predictor among the natural factors (β = −0.14), whereas population density stood out as the foremost predictor among the anthropogenic factors (β = 0.23). Notably, both climatic conditions and anthropogenic factors contributed positively to an increase in ancient tree biomass (β = 0.02) (β = 0.07), albeit concurrently leading to a decrease in species richness (β = −0.05) (β = −0.08). In regions characterized by high levels of disturbance, anthropogenic factors indirectly increase biomass by increasing the abundance of large-diameter ancient trees (β = 0.28) while concurrently decreasing species richness (β = −0.11). Conversely, in areas with low levels of disturbance, anthropogenic influences also indirectly increase biomass (β = 0.19) by fostering the growth of large-diameter ancient trees while simultaneously promoting species richness (β = 0.01). This study investigated biomass and diversity factors in ancient trees within human-dominated regions of Guangdong Province. This study provides insights into ecosystem determinants, informing conservation strategies and contributing to biodiversity preservation amid societal and environmental dynamics.

Genetic analysis of preaxial polydactyly: identification of novel variants and the role of ZRS duplications in a Chinese cohort of 102 cases.

Preaxial polydactyly (PPD) is a congenital limb malformation, previously reported to be caused primarily by variants in the ZRS and upstream preZRS regions. This study investigated genetic variations associated with PPD, focusing on point variants and copy number variations (CNVs) in the ZRS and preZRS regions. Comprehensive genetic analyses were conducted on 102 patients with PPD, including detailed clinical examinations and Sanger sequencing of the ZRS and preZRS regions. Additionally, real-time quantitative PCR (qPCR) was used to detect CNVs in the ZRS region. The evolutionary conservation and population frequencies of identified variants were also evaluated. Six point variants were identified, among which four are likely pathogenic novel variants: 93G > T (g.156584477G > T), 106G > A (g.156584464G > A), 278G > A (g.156584292G > A), and 409A > C (g.156585378A > C). Additionally, qPCR analysis revealed that 66.67% of patients exhibited ZRS duplications. Notably, these duplications were also present in cases with newly identified potential pathogenic point variants. These findings suggest the possible interaction of point variants in ZRS and preZRS through a common pathogenic mechanism, leading jointly to PPD. The findings expand the variant spectrum associated with non-syndromic polydactyly and highlight that, despite different classifications, anterior polydactyly caused by variants in ZRS and nearby regions may share common pathogenic mechanisms. The incorporation of various variant types in genetic screening can effectively enhance the rate of pathogenic variant detection and contribute to the cost-effectiveness of genetic testing for limb developmental defects, thereby promoting healthy births.

Unravelling the architecture of major histocompatibility complex class II haplotypes in rhesus macaques.

The regions in the genome that encode components of the immune system are often featured by polymorphism, copy number variation, and segmental duplications. There is a need to thoroughly characterize these complex regions to gain insight into the impact of genomic diversity on health and disease. Here we resolve the organization of complete major histocompatibility complex (MHC) class II regions in rhesus macaques by using a long-read sequencing strategy (Oxford Nanopore Technologies) in concert with adaptive sampling. In particular, the expansion and contraction of the primate DRB-region appear to be a dynamic process that involves the rearrangement of different cassettes of paralogous genes. These chromosomal recombination events are propagated by a conserved pseudogene, DRB6, which features the integration of two retroviral elements. In contrast, the DRA locus appears to be protected from rearrangements, which may be owing to the presence of an adjacently located truncated gene segment, DRB9 With our sequencing strategy, the annotation, evolutionary conservation, and potential function of pseudogenes can be reassessed, an aspect that was neglected by most genome studies in primates. Furthermore, our approach facilitates the characterization and refinement of an animal model essential to study human biology and disease.

Diversity of transactivation regions of DMRT1 in vertebrates

BackgroundDoublesex and mab-3 related transcription factor (DMRT) 1, commonly found in all vertebrates, regulates the transcription of genes involved in the masculinization and maintenance of gonadal somatic cells and/or germline cell development. DMRT1 has a DNA-binding domain called the DM domain and a transcription regulatory region. Unlike the former, there is little knowledge about the latter transcription regulatory region. This study aimed to identify the transcription activation regions of DMRT1 from four species: humans and mice (mammals), leopard geckos (reptiles), and medaka (teleost fish), adding perspectives on evolutionary conservation and diversity.Methods and resultsFor each species, several expression plasmids of deletion mutants were constructed, and the resultant plasmid and a DMRT1-driven luciferase reporter were co-transfected into cultured cells to measure transactivation ability. The key point of this analysis is that the transactivation ability was normalized by quantifying the expression levels of DMRT1 variants using the HiBiT tag. As a result, two to three transactivation regions were suggested to exist in the C-terminal region of the DM domain in all four species. Among seven regions in DMRT1, the fourth region from the N-terminus contributed to transactivation common to the four species, and the sixth and seventh regions on the C-terminal side differed depending on the species.ConclusionsThese findings indicated that the regions involved in the transactivation ability of DMRT1 could subtly change during evolution, indicating diversity in transactivation domains.

Behavioral screening reveals a conserved residue in Y-Box RNA-binding protein required for associative learning and memory in C. elegans.

RNA-binding proteins (RBPs) regulate translation and plasticity which are required for memory. RBP dysfunction has been linked to a range of neurological disorders where cognitive impairments are a key symptom. However, of the 2,000 RBPs in the human genome, many are uncharacterized with regards to neurological phenotypes. To address this, we used the model organism C. elegans to assess the role of 20 conserved RBPs in memory. We identified eight previously uncharacterized memory regulators, three of which are in the C. elegans Y-Box (CEY) RBP family. Of these, we determined that cey-1 is the closest ortholog to the mammalian Y-Box (YBX) RBPs. We found that CEY-1 is both necessary in the nervous system for memory ability and sufficient to promote memory. Leveraging human datasets, we found both copy number variation losses and single nucleotide variants in YBX1 and YBX3 in individuals with neurological symptoms. We identified one predicted deleterious YBX3 variant of unknown significance, p.Asn127Tyr, in two individuals with neurological symptoms. Introducing this variant into endogenous cey-1 locus caused memory deficits in the worm. We further generated two humanized worm lines expressing human YBX3 or YBX1 at the cey-1 locus to test evolutionary conservation of YBXs in memory and the potential functional significance of the p.Asn127Tyr variant. Both YBX1/3 can functionally replace cey-1, and introduction of p.Asn127Tyr into the humanized YBX3 locus caused memory deficits. Our study highlights the worm as a model to reveal memory regulators and identifies YBX dysfunction as a potential new source of rare neurological disease.

The Neural Correlations of Olfactory Associative Reward Memories in Drosophila.

Advancing treatment to resolve human cognitive disorders requires a comprehensive understanding of the molecular signaling pathways underlying learning and memory. While most organ systems evolved to maintain homeostasis, the brain developed the capacity to perceive and adapt to environmental stimuli through the continuous modification of interactions within a gene network functioning within a broader neural network. This distinctive characteristic enables significant neural plasticity, but complicates experimental investigations. A thorough examination of the mechanisms underlying behavioral plasticity must integrate multiple levels of biological organization, encompassing genetic pathways within individual neurons, interactions among neural networks providing feedback on gene expression, and observable phenotypic behaviors. Model organisms, such as Drosophila melanogaster, which possess more simple and manipulable nervous systems and genomes than mammals, facilitate such investigations. The evolutionary conservation of behavioral phenotypes and the associated genetics and neural systems indicates that insights gained from flies are pertinent to understanding human cognition. Rather than providing a comprehensive review of the entire field of Drosophila memory research, we focus on olfactory associative reward memories and their related neural circuitry in fly brains, with the objective of elucidating the underlying neural mechanisms, thereby advancing our understanding of brain mechanisms linked to cognitive systems.