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Systematic identification pepper CaE2F transcription factor reveals the role of CaDPb in drought stress response.

The EARLY 2 FACTOR (E2F) transcription factor (TF) family plays a pivotal role in regulating plant development and adaptations to environmental stresses. However, the physiological function of E2Fs in pepper (Capsicum annuum L.) are not well elucidated. In this work, we conduct a comprehensive genome-wide annotation of the E2F family within the Zunla-1 pepper genome and further explore the biological roles of CaDPb in response to drought stress. Through systematic bioinformatics analysis, we identify a total of nine CaE2F genes within the Zunla-1 genome, categorizing them into three distinct subgroups. Additionally, we discover multiple cis-regulatory elements in the CaE2F promoter regions associated with responses to plant hormones and drought stress. Public RNA-seq datasets reveal distinct expression profiles of CaE2F genes across various pepper tissues and their responses to environmental stimuli and plant hormones. Subsequently, the CaDPb gene is further functionally verified in drought response. Our findings indicate that TRV2:CaDPb silenced pepper plants are more sensitivity to drought. Furthermore, we show that CaDPb participates in the regulation of reactive oxygen species (ROS) production, the expression of drought-responsive genes, and the modulation of stomatal aperture. Taken together, our findings provide a comprehensive characterization of E2F genes in pepper and offer insights into the biological function of CaDPb in pepper drought stress response.

Capsicum↗

DeepGeSeq: deep learning library for genomic sequence modeling and analysis.

MOTIVATION: Deep learning methods have demonstrated significant potential in genomics, enabling broad applications such as sequence activity prediction, regulatory rule identification, and variant effect quantification. However, their widespread adoption is often hindered by the steep computational learning curve required for model construction, training, and downstream biological interpretation. Here, we introduce DeepGeSeq, a user-friendly Deep-learning library tailored for Genomic Sequence modeling and analysis. RESULTS: By integrating state-of-the-art architectural modules, DeepGeSeq streamlines the entire deep learning workflow, requiring minimal user input via a simple configuration file and an intuitive agentic skill. We comprehensively validate the efficacy of DeepGeSeq through diverse case studies, encompassing pipeline verification using synthetic datasets, the reproduction and application of established models, and model fine-tuning coupled with biological interpretation on user-defined data. Furthermore, we demonstrate DeepGeSeq's versatility in domain-specific applications, including single-cell ATAC-seq modeling for cell-type clustering, and MPRA data modeling coupled with in silico saturation mutagenesis to dissect cis-regulatory elements. Ultimately, DeepGeSeq bridges the gap between computational complexity and biological discovery, providing an accessible resource that facilitates the development and broad application of deep learning methods in genomics research. AVAILABILITY AND IMPLEMENTATION: https://github.com/JiaqiLi1024/DeepGeSeq.

Deep Learning↗

Human thioredoxin/adult T cell leukemia-derived factor activates the enhancer binding protein of human immunodeficiency virus type 1 by thiol redox control mechanism.

Transcription from the human immunodeficiency virus type 1 (HIV-1) provirus is activated by a cellular factor, NF kappa B, recognizing the tandemly repeated 10-base-pair sequences, termed the kappa B sequence, present in the enhancer region within the viral long terminal repeat (LTR). Using electrophoretic mobility shift assay (EMSA), which demonstrates specific DNA-protein interaction in vitro, we could demonstrate that reducto-oxidative modulation of NF kappa B dramatically changes its DNA binding activity and that a cellular physiological reducing catalyst, thioredoxin (TRX) also known as adult T cell leukemia derived factor (ADF), fully restored the DNA-binding activity of the oxidized NF kappa B. We also observed that purified TRX/ADF protein could augment gene expression from HIV LTR as demonstrated by transient chloramphenicol acetyltransferase (CAT) assay. These observations confirmed the previous notion that ADF might be an inducing factor of cellular interleukin-2 receptor alpha subunit (IL-2R alpha) through the kappa B sequence that is a common central cis-regulatory element in both IL-2R alpha and HIV gene expression. These observations indicate that reducto-oxidative regulation (or redox regulation) of a cysteine residue(s) on the NF kappa B molecule might play an important role in its specific DNA interaction and that it might provide a clue to the understanding of a pathway of cellular signal transduction to NF kappa B that is independent from the known pathways involving protein phosphorylation.

Amino Acid Sequence↗

dbscATAC: a resource of single-cell super-enhancers/enhancers and gene markers derived from scATAC-seq data.

MOTIVATION: scATAC-seq enables high-resolution mapping of cis-regulatory elements. It has been widely applied to uncover cell-type-specific regulatory networks and complement scRNA-seq analysis in numerous studies. However, a large number of datasets generated by scATAC-seq remain underutilized due to limited exploration of super-enhancers/typical enhancers and gene markers. A comprehensive resource enabling cell-type-specific annotation of cis-regulatory elements and their dynamic enhancer-gene linkages remains an urgent unmet need for scATAC-seq. RESULTS: We present dbscATAC, a specialized single-cell database for annotating super-enhancers, gene markers, and enhancer-gene interactions derived from scATAC-seq data. Using improved machine learning algorithms, we identified 213 835 super-enhancers across 520 tissue/cell types from three species, as well as 347 484 gene markers, 13 470 526 enhancers, and 10 402 346 enhancer-gene interactions derived from 1 668 076 single cells spanning 1028 tissue/cell types in 13 species. An easy-to-use online platform with multiple analytic modules and hierarchical query options was developed for searching, browsing and visualizing single-cell super-enhancers, enhancers, and gene markers. dbscATAC provides a comprehensive resource to facilitate the exploration of enhancer landscapes, gene regulation, and cell-type-specific characteristics in single-cell epigenomics. AVAILABILITY AND IMPLEMENTATION: The database with all the super-enhancer/enhancer annotation data is available at http://singlecelldb.com/dbscATAC/index.php. And the source code of dbscATAC for prediction of SEs, enhancers, and gene markers are available at https://github.com/EvansGao/dbscATAC. The source code, tissue/cell type description, and data summary can be downloaded at DOI: 10.6084/m9.figshare.28706414.scATAC-seq, Database, Super-enhancers/enhancers, Gene markers.

Enhancer Elements, Genetic↗

Transcriptional control of human papillomavirus (HPV) oncogene expression: composition of the HPV type 18 upstream regulatory region.

The malignant transformation potential of high-risk human papillomaviruses (HPVs) is closely linked to the expression of the viral E6 and E7 genes. To elucidate the molecular mechanisms resulting in HPV oncogene expression, a systematic analysis of the cis-regulatory elements within the HPV type 18 (HPV18) upstream regulatory region (URR) which regulate the activity of the E6/E7 promoter was performed. As the functional behavior of a given cis-regulatory element can be strongly influenced by the overall composition of a transcriptional control region, individual elements were inactivated by site-directed mutagenesis in the physiological context of the complete HPV18 URR. Subsequently, the effects of these mutations on the activity of the E6/E7 promoter were assessed by transient transfection assays. We found that the transcriptional stimulation of the E6/E7 promoter largely depends on the integrity of cis-regulatory elements bound by AP1, SP1, and in certain epithelial cells, KRF-1. In contrast to previous reports by implying a key role for NF1 and Oct-1 recognition motifs in the stimulation of papillomavirus oncogene expression, the inactivation of these elements in the context of the HPV18 URR did not strongly affect the transcriptional activity of the E6/E7 promoter. Mutation of a promoter-proximal glucocorticoid response element completely abolished dexamethasone inducibility of the HPV18 E6/E7 promoter and resulted in an increase of its basal activity. Functional dissection of the HPV18 constitutive enhancer region indicates that its transcriptional activity is largely generated by functional synergism between a centrally located AP1 module and thus far undetected cis-active elements present in the 5' flank of the enhancer. Furthermore, comparative analyses using homologous and heterologous promoters show that the transcriptional activity of HPV18 enhancer elements is influenced by the nature of the test promoter in a cell-type-specific manner.

Base Sequence↗

Developmental patterning of adipose tissue by abd-A and Abd-B homeotic genes in Drosophila melanogaster.

The Bithorax Complex (BX-C) homeobox proteins specify segmental identities along the anterior-posterior axis during Drosophila embryogenesis. Differential expression of the BX-C genes abd-A and Abd-B distinguishes abdominal from thoracic adipocytes, yet the mechanism regulating this heterogeneity remains poorly understood. Here, we identify cis-regulatory elements (CREs) and transcription factors that direct abdominal-specific expression of abd-A and Abd-B in the larval fat body. Fine-mapping analyses identified a 627-bp CRE within the Abd-B locus and a ~6-kb CRE within the abd-A locus sufficient to drive heterogeneous expression. Yeast one-hybrid screening combined with functional analyses identified Lola, Lolal, and Combgap as key repressors of Abd-B, whereas Piragua (Prg) and Seven up (Svp) function as transcriptional activators, indicating that adipocyte heterogeneity in postembryonic adipose tissue is actively regulated. In turn, lola and prg are repressed by Abd-B, whereas lolal and svp are activated, forming a feedback circuit further modulated by Wnt signaling, which promotes lola and lolal expression while repressing svp. CUT&RUN analyses suggest that these interactions are direct, with dTCF/Pan and Abd-B occupancy detected at target loci. Together, our findings define a transcriptional circuit that regulates Abd-B gene transcription to pattern adipose tissue and may establish the developmental basis of fat depot specialization.

Abd-B↗

Tumor necrosis factor-alpha down-regulates human elastin gene expression. Evidence for the role of AP-1 in the suppression of promoter activity.

Cytokine modulation of elastin gene expression was examined by assay of elastin mRNA abundance and by transient transfections of cultured human skin fibroblasts and rat aortic smooth muscle cells with elastin promoter/reporter gene (chloramphenicol acetyltransferase, CAT) constructs. Incubation of cells with human recombinant tumor necrosis factor-alpha (TNF-alpha) markedly suppressed the elastin mRNA levels in a time- and dose-dependent manner by up to 91%. TNF-alpha also suppressed the expression of the elastin promoter/CAT construct by up to 70% in transiently transfected cells, indicating regulation at the transcriptional level. This suppression was temporally preceded by rapid and transient up-regulation of c-jun and c-fos genes. The down-regulatory effect of TNF-alpha on elastin promoter activity was abolished by co-transfections with a synthetic double-stranded AP-1 oligomer. Furthermore, co-transfection of the elastin promoter construct with c-jun and c-fos expression plasmids resulted in a marked decrease in the promoter activity. Elucidation of the cis-regulatory elements in the elastin promoter by 5' deletion construct analysis implicated a region -290 to -198 containing one AP-1 binding site. The functional role of this AP-1 site was further tested by gel retardation assays which indicated formation of a DNA-protein complex specific for TNF-alpha treated cells. This complex could be partially dissociated by a competing oligomer containing the consensus AP-1 binding site. These observations suggest that the inhibitory effects of TNF-alpha on elastin gene expression involve the transcription factor AP-1. Interferon-gamma also suppressed the elastin gene expression at the mRNA level by approximately 52%, but it had no effect on the elastin promoter activity, suggesting post-transcriptional mechanisms. These results indicate that mediators released from inflammatory cells can modulate elastin gene expression, and such modulation may play a role in diseases characterized by altered accumulation of elastic fibers in tissues.

Adult↗

Transactivation activity of Maf nuclear oncoprotein is modulated by Jun, Fos and small Maf proteins.

The v-maf oncogene encodes a nuclear bZip protein which specifically recognizes relatively long palindromic sequences related to an AP-1 site. In this study, we investigated the relationship of transactivation and transformation activity of Maf. The amino-terminal two thirds of the molecule were dispensable for its DNA-binding activity but conferred its transactivation potential. Transactivation activities of a set of deletion mutants correlated well with their cell transforming abilities. However, a point mutant associated with enhanced oncogenic activity was not more effective in transactivation than the wild type, suggesting that some other function(s) of Maf is also important for its transforming ability. We also examined the effect of other bZip proteins on the transactivation activity of Maf. Three small Maf family proteins (MafK, MafF and MafG), which are missing the transactivation domain of v-Maf, competitively inhibited transactivation by Maf. Co-expression of Jun or Fos also affected the transactivation potential of Maf by forming Maf/Jun or Maf/Fos heterodimers of distinct DNA-binding specificities. In addition to these factors, we noticed the presence of a strong endogenous transactivating activity associated with a sequence related to an NF-E2 site rather than the typical AP-1 site in fibroblast cells. These results indicate that AP-1 site-like cis-regulatory elements of eukaryotic genes are regulated by multiple sets of bZip dimers with different DNA-binding and transactivation properties.

3T3 Cells↗

Conserved HSFA1-dependent chromatin dynamics drive heat stress responses in plants.

Eukaryotic organisms remodel chromatin landscapes to regulate gene expression in response to environmental stress. In plants, heat stress (HS) induces widespread chromatin changes, yet the role of heat shock transcription factors (HSFs) in chromatin remodeling and their evolutionary conservation remains unclear. Using Marchantia polymorpha Mphsf mutants and Arabidopsis thaliana Athsfa1s mutants, we identify HSFA1 as a key regulator of HS-induced cis-regulatory element (CRE) accessibility, a mechanism conserved across land plants, mice, and humans. Gene regulatory network modeling reveals parallel transcription factor subnetworks, with MpWRKY10 and MpABI5B acting as indirect and negative HS regulators. We further showed that ABA modulates gene expression in an HSFA1-dependent manner without inducing chromatin remodeling. Finally, we develop a machine learning framework integrating chromatin accessibility and CRE information to predict gene expression across species, revealing stress-responsive regulatory logic at the transcriptional level. These findings provide insights into how TFs coordinate chromatin architecture to drive stress adaptation.

Heat-Shock Response↗

Genome-wide identification, characterization, and expression pattern analysis of the glyoxalase gene family in Phyllostachys pubescens during abiotic stresses.

BACKGROUND: The glyoxalase pathway comprising of three enzymes i.e., glyoxalase I (GLYI), glyoxalase II (GLYII), and glyoxalase III (GLYIII), which play vital role in mitigating abiotic stresses by detoxifying the stress induced cytotoxic metabolite methylglyoxal (MG). Phyllostachys pubescens an ecologically and economically important forest species, plays vital roles in carbon sequestration and climate change mitigation. A genome-wide study was conducted to identify and characterize GLYI, GLYII, and unique DJ-1/GLYIII gene candidates in P. pubescens. The identified members were evaluated based on phylogenetic analysis, gene structure, chromosomal distribution, gene duplication, presence of conserved domain(s) and cis regulatory region. RESULTS: A total of 19 GLYI, 18 GLYII, and 15 GLYIII members were identified, each featuring characteristic domains: glyoxalase, metallo-β-lactamase, and DJ-1/PfpI, respectively. The presence of different cis-elements in the promoter region of the glyoxalase genes gives insights into their role and regulation under hormonal response, developmental processes and stress adaptation. Besides this, stress responsive transcription factors binding sites also dominated the promoter regions of glyoxalase genes. Expression analysis of various glyoxalase genes demonstrated significant variability under different stress conditions, underscoring their potential roles in stress modulation. Significant upregulation of all of the PhGLYI, PhGLYII, and PhGLYIII were observed under cold, drought, heavy metal and salinity stress suggesting their involvement in oxidative stress management, osmotic regulation and remodelling cellular redox homeostasis. Among the glyoxalase genes, PhGLYI-15, PhGLYII-9, and PhGLYIII-3 showed consistent upregulation under various abiotic stresses. CONCLUSIONS: Our findings reveal that glyoxalase genes crucially contribute towards the improvement of cellular osmotic potential in moso bamboo under different abiotic stresses. This study enhances our understanding of glyoxalase genes' evolution and functional roles in plants and opens new avenues for developing stress resilient crop varieties for sustainable agriculture.

Lactoylglutathione Lyase↗

Induction of human tenascin (neuronectin) by growth factors and cytokines: cell type-specific signals and signalling pathways.

The extracellular matrix protein tenascin (TN) is expressed with precise temporo-spatial patterns during embryonic and fetal development and is induced in healing wounds, inflammatory lesions and solid tumors. These tissue patterns suggest that TN synthesis may be modulated by soluble factors present in developing tissues or released from injured, inflammatory or neoplastic cells. To characterize the extrinsic control of human TN we examined the effects of several signalling molecules on cultured neural, melanocytic and fibroblastic cells. Results obtained with alpha TN antibodies in enzyme-linked immunosorbent and immunoprecipitation assays indicate that TN expression is tightly regulated in a cell type-specific manner: (1) Primitive neuroectodermal tumor (PNET) cells grown in chemically defined, serum-free media show up to > 100-fold TN induction in response to fibroblast growth factors (aFGF, bFGF, K-FGF) and phorbol ester, independent of changes in cell proliferation or total protein synthesis; no induction is seen in PNET cultures stimulated with serum or other growth and differentiation factors. (2) Normal melanocytes, which require FGF and phorbol ester for survival in vitro, fail to express TN; however, they produce TN following oncogenic transformation. (3) Fibroblasts derived from disparate tissues differ up to 100-fold in basal TN production; for example, fetal lung fibroblasts are TNhigh, but conjunctival fibroblasts derived from the same donors and fetal leptomeningeal cells are TNlow. (4) TNlow fibroblasts treated with interleukin-1, tumor necrosis factor-alpha, and interleukin-4 show up to > 100-fold increased TN secretion and TN incorporation into their extracellular matrix. Transforming growth factor-beta, which acts as an inducer of fibronectin, collagen, and integrin-type matrix receptors, has variable effects on fibroblast TN, ranging from increased deposition in the extracellular matrix of fetal conjunctival fibroblasts to reduced secretion in newborn foreskin fibroblasts. In contrast, FGFs (which are potent fibroblast mitogens), phorbol ester, bone morphogenetic proteins, and several other factors tested produced no discernible effects on fibroblast TN expression. These findings suggest that discrete sets of extrinsic signals modify TN expression in specific cell types, with the effects of a given ligand/receptor system determined by cell type-specific signalling pathways that may be linked to unique cis-regulatory elements of the TN gene. As a result, a limited set of regulatory peptides may produce highly diversified TN distribution patterns in developing and lesional tissues.

Cell Adhesion Molecules, Neuronal↗

Cell cycle controlled histone H1, H3, and H4 genes share unusual arrangements of recognition motifs for HiNF-D supporting a coordinate promoter binding mechanism.

Cell cycle and growth control of the DNA binding and transactivation functions of regulatory factors provides a direct mechanism by which cells may coordinate transcription of a multitude of genes in proliferating cells. The promoters of human DNA replication dependent histone H4, H3, and H1 genes interact with at least seven distinct proteins. One of these proteins is a proliferation-specific nuclear factor, HiNF-D, that interacts with a key cis-regulatory element (H4-Site II; 41 bp) present in H4 genes. Here we describe binding sites for HiNF-D in the promoters of H3 and H1 genes using cross-competition, deletion analysis, and methylation interference assays, and we show that HiNF-D recognizes intricate arrangements of at least two sequence elements (CA- and AG-motifs). These recognition motifs are irregularly dispersed and distantly positioned in the proximal promoters (200 bp) of both the H3 and H1 genes. In all cases, these motifs either overlap or are in close proximity to other established transcriptional elements, including ATF and CCAAT sequences. Although HiNF-D can interact with low affinity to a core recognition domain, auxiliary elements in both the distal and proximal portions of each promoter cooperatively enhance HiNF-D binding. Thus, HiNF-D appears to bridge remote regulatory regions, which may juxtapose additional trans-activating proteins interacting within histone gene promoters. Consistent with observations in many cell culture systems, the interactions of HiNF-D with the H4, H3, and H1 promoters are modulated in parallel during the cessation of proliferation in both osteosarcoma cells and normal diploid osteoblasts, and these events occur in conjunction with concerted changes in histone gene expression. Thus, HiNF-D represents a candidate participant in coordinating transcriptional control of several histone gene classes.

Base Sequence↗

A wild soybean MADS-box gene GsAGL62 improves seed weight by enhancing cytokinin signaling and cell proliferation.

Soybean seed weight is a key yield determinant, but the transcriptional mechanisms connecting hormone signaling to seed growth are poorly understood. Here, we identify GsAGL62, a wild soybean MADS-box transcription factor located within a previously mapped hundred-seed weight (HSW) locus and a domestication-associated selective sweep. Functional analyses show that overexpression of GsAGL62 in cultivated soybean significantly increases HSW, whereas ethyl methanesulfonate (EMS)-induced gmagl62 mutants reduce it. Integrated transcriptomic and metabolomic analyses reveal that GsAGL62 enhances cytokinin accumulation and signaling cytokinin-associated responses, accompanied by increased expression of genes involved in cell proliferation. Mechanistically, GsAGL62 directly binds to the promoter of the conserved growth inhibitor GmATPK2 and represses its transcription. Consistently, independent EMS-induced gmatpk2 mutants exhibit increased seed weight, supporting GmATPK2 as a downstream negative regulator of seed growth. Population genetic analyses further reveal strong differentiation of GsAGL62 promoter haplotypes during soybean domestication and improvement. These haplotypes show differential promoter activities and are associated with distinct agronomic performance, suggesting that cis-regulatory variation at GsAGL62 contributes to its selection during soybean improvement. Collectively, our findings establish a regulatory module linking GsAGL62 to cytokinin-associated responses, cell proliferation, and seed growth, and highlight GsAGL62 as a potential target for soybean yield improvement.

Cell proliferation↗

A cis-regulatory allele of ZmNPR1I spatially uncouples flowering from stalk-rot resistance in maize.

Pleiotropic effects of adaptive genes frequently constrain crop improvement by coupling beneficial traits with unfavorable trade-offs. In maize, ZmCCT10 confers strong stalk-rot resistance but causes delayed flowering under long-day conditions, limiting its deployment in temperate breeding. Here, we identify qPss3 as a cis-regulatory locus that governs its downstream target gene, ZmNPR1I. The ZmNPR1I protein represses ZmCCT10 transcription and, together with ZmNPR1-3, facilitates ZmCCT10 protein degradation. The favorable qPss3A5 allele reduces ZmNPR1I expression in leaves, relieving repression of ZmCCT10, ZmSPL32, and ID1, which collectively enhance ZCN8 expression to accelerate flowering. In roots, however, pathogen-induced activation of the resistant ZmCCT10H5 allele largely bypasses qPss3 regulation, thereby preserving stalk-rot resistance. Introgression of qPss3A5 into ZmCCT10H5-containing maize germplasm restores flowering adaptation without compromising disease resistance, improving yield stability under disease pressure. Our work reveals a tissue-specific qPss3A5-ZmNPR1I regulatory module that uncouples the developmental and immune functions of a pleiotropic adaptive gene, providing a general strategy for optimizing beneficial alleles in crop breeding.

flowering time↗

Genetic analysis of transvection effects involving cis-regulatory elements of the Drosophila Ultrabithorax gene.

The Ultrabithorax (Ubx) gene of Drosophila melanogaster contains two functionally distinguishable regions: the protein-coding Ubx transcription unit and, upstream of it, the transcribed but nonprotein-coding bxd region. Numerous recessive, partial loss-of-function mutations which appear to be regulatory mutations map within the bxd region and within the introns of the Ubx transcription unit. In addition, mutations within the Ubx unit exons are known and most of these behave as null alleles. Ubx1 is one such allele. We have confirmed that, although the Ubx1 allele does not produce detectable Ubx proteins (UBX), it does retain other genetic functions detectable by their effects on the expression of a paired, homologous Ubx allele, i.e., by transvection. We have extended previous analyses made by E. B. Lewis by mapping the critical elements of the Ubx gene which participate in transvection effects. Our results show that the Ubx1 allele retains wild-type functions whose effectiveness can be reduced (1) by additional cis mutations in the bxd region or in introns of the Ubx transcription unit, as well as (2) by rearrangements disturbing pairing between homologous Ubx genes. Our results suggest that those remnant functions in Ubx1 are able to modulate the activity of the allele located in the homologous chromosome. We discuss the normal cis regulatory role of these functions involved in trans interactions between homologous Ubx genes, as well as the implications of our results for the current models on transvection.

Alleles↗

Integrative Genomic, Transcriptomic and Epigenomic Analysis Reveals cis-regulatory Contributions to High-altitude Adaptation in Tibetan Pigs.

The Qinghai-Tibet Plateau, characterized by its extreme environmental conditions, presents significant challenges to life, making it an ideal region for studying adaptation and evolution. Tibetan pigs, known for their high genetic diversity and exceptional adaptability to high altitudes, serve as excellent models for investigating high-altitude adaptation. While previous studies have extensively identified genetic determinants associated with high-altitude adaptation, the molecular mechanisms, particularly cis-regulatory patterns, remain poorly understood. Here, we conducted a selective sweep analysis using 484 genomes from Chinese and Western pig breeds across various altitudes, revealing 38.56 Mb of genomic regions under selection in Tibetan pigs. Enrichment analysis identified the lung as the primary functional tissue involved in high-altitude adaptation, supported by tissue-specific transcriptional and regulatory patterns observed between Tibetan and Meishan pigs (low altitude). By integrating genomic, RNA-seq, ATAC-seq, and H3K27ac HiChIP data, we constructed comprehensive enhancer-promoter regulatory maps of candidate genes and pinpointed promising genetic determinants associated with high-altitude adaptation, including SNPs in EPAS1, KLF13, SPRED1, and CFD. These loci were predicted to influence chromatin accessibility and the interactions of regulatory elements, with altered binding strength of relevant transcription factors. Further in vitro experiments confirmed that these loci function as allele-specific enhancers, modulating the expression of target genes. Our findings elucidate the regulatory basis of high-altitude adaptation in Tibetan pigs and provide valuable insights for exploring hypoxia-related diseases in livestock and humans.

Animals↗

Proximal cis-acting elements cooperate to set Hoxb-7 (Hox-2.3) expression boundaries in transgenic mice.

The Hox genes have been proved to be instrumental in establishing the positional identity of cells along the embryonic anteroposterior (A-P) axis. Studying the regulation of these genes is a first step toward elucidating the molecular basis of regionalization during embryogenesis. We report here on the identification of cis-acting elements controlling the expression of Hoxb-7 (Hox-2.3). We show that elements driving A-P restricted gene expression are located within the 3.5 kb proximal upstream sequences of the Hoxb-7 gene. A deletion analysis provides evidence for at least three cis-acting control elements upstream from Hoxb-7, and for cooperative interactions between some of these elements in generating the A-P restricted transgenic pattern. One element, conferring by itself Hox-like expression boundaries to the transgene, has been studied in more detail and found to act in an orientation-and promoter-dependent manner. Together the 3.5 kb sequences proximal to Hoxb-7 mediate A-P restricted Hoxb-7/lacZ gene expression in a domain showing rostral boundaries more posterior than those of Hoxb-7. The evolution throughout embryogenesis of the expression pattern of a transgene carrying these sequences has been analysed and shown to mimick that of the endogenous gene, except for a slight delay in the initial expression. We conclude that the transgenes that we tested, spanning a total of 27 kb genomic sequences, do not reproduce all the features of the Hoxb-7 expression pattern. The differences in expression between Hoxb-7 and the transgenes may reveal an aspect of the Hox regulation for which either remote cis-acting control elements and/or gene clustering is required. Additional features that may have favoured maintenance of clustered organisation during evolution are partial overlap of transcription units with the regulatory regions of the neighbouring genes, and cis-regulatory interactions between multiple Hox genes: not only do cis-acting control elements of the Hoxb-7 gene map in the 3' untranslated sequences of the Hoxb-8 (Hox-2.4) gene, but our experiments suggest that Hoxb-7 control sequences modulate expression of the Hoxb-8 gene as well.

Animals↗

Spatial and temporal information processing in the sea urchin embryo: modular and intramodular organization of the CyIIIa gene cis-regulatory system.

The CyIIIa cytoskeletal actin gene of Strongylocentrotus purpuratus is expressed specifically in the aboral ectoderm. In earlier work we identified a 2.3 kb cis-regulatory region that is necessary and sufficient for correct spatial and temporal expression of a CyIIIa.CAT gene. This region includes about 20 sites of specific protein-DNA interaction, at which at least nine different transcription factors may be bound. All except two of these factors have been cloned. In this work we have analyzed by deletion or mutagenesis each specific interaction. A specific function was identified for every binding site examined. These individual functions include control of amplitude and timing of expression at different phases of embryogenesis, and control of spatial expression. We show that particular negative regulatory interactions are required to repress expression of the CyIIIa.CAT construct in oral ectoderm and in skeletogenic mesenchyme at different stages. In further experiments we determined the overall functional organization of the CyIIIa cis-regulatory system, and we show that this system is modular in its regulatory structure. The 'proximal module' (with respect to the transcription start site) extends upstream for about 800 base pairs, and includes nine target sites serviced by six different transcription factors. Its major role is to establish CyIIIa expression in the aboral ectoderm territory as the blastomere founder cells are specified and the oral-aboral axis is determined, and to activate the CyIIIa gene late in cleavage. The 'middle module,' which lies upstream of the proximal module, acquires major control of CyIIIa function after the blastula stage. It includes six target sites, serviced by four different factors. The middle module is responsible for a sharp increase in expression occurring during gastrulation, mediated by the positively acting factors that bind within it. The middle module also includes sites at which two different negatively acting spatial control factors bind, the functions of which are required for correct spatial expression late in embryogenesis. The 'distal module' contains a number of sites at which a positively acting factor binds, but this module exercises no spatial regulatory function. Interactions within the distal module are required for the normal levels of function of both the proximal and middle modules.

Actins↗