Project description:Purpose: Determine whether sex-determining genes are bivalent at the bipotential stage, poised between the testis and ovary fate, and whether H3K4me3 and H3K27me3 resolve into sex-specific patterns after sex determination, contributing to the canalization and stabilization of either the testis or ovary fate. Methods: XX and XY supporting cells of the gonad were FACS-purified before sex determination (at E10.5) and after sex determination (at E13.5), and submitted to ChIP-seq for H3K4me3, H3K27me3 and H3 as a means to normalize across cell populations. Results: We found that key sex-determining genes are bivalent at the bipotential stage. Genes that are upregulated affter sex determination are stripped of their repressive H3K27me3 mark, whereas repressed genes that promote the alternate pathway remain bivalent even after sex determination.
Project description:Transcriptomic changes following recent natural hybridization and allopolyploidy in the salt marsh species Spartina x townsendii and Spartina anglica (Poaceae) Allopolyploidy results from two events: the merger of divergent genomes and genome duplication. Both events have important functional consequences for the evolution and adaption of newly formed allopolyploid species. In spite of significant progress made the last years, a few studies have decoupled the effects of hybridization from genome duplication in the observed patterns of expression changes accompanying allopolyploidy in natural conditions. We used Agilent Rice oligo-microarrays to explore gene expression changes following allopolyploidy in Spartina that includes a classical example of recent allopolyploid speciation, S. anglica formed during the 19th century following genome duplication of the hybrid S. x townsendii. Our data indicate important, thought different effects of hybridization and genome duplication in the expression patterns of the hybrid and allopolyploid. Deviation from parental additivity was most important following hybridization and was accompanied by maternal expression dominance, although transgressively expressed genes were also encountered. Maternal dominance is attenuated following genome duplication in S. anglica while this species exhibits an increased number of transgressively over expressed genes. These results reflect the decoupled effects of the “genomic shock” following hybridization and genome redundancy, on the genetic, epigenetic and regulatory mechanisms characterizing transcriptomic evolution in allopolyploids. We used Agilent Rice oligo-microarrays to explore gene expression changes among Spartina species, following interspesific hybridization and genome duplication (allopolyploidy). The analysed species included the parents S. maritima & S.alterniflora, the hybrid F1 S x. towensendii and the allopolyploid S.anglica. A total of 20 slides (five replicates per species) were hybridized on a 44 K Rice Agilent array using a one color desgin.
Project description:Developmental gene expression is defined through cross-talk between the function of transcription factors and epigenetic status including histone modification. Although several known transcription factors play crucial roles in mammalian sex determination, how chromatin regulation contributes to this process is unknown. We observed male-to-female sex reversal in mice lacking the H3K9 demethylase Jmjd1a, and found that Jmjd1a directly regulates expression of the mammalian Y chromosome sex-determining gene Sry, by regulating H3K9me2 marks. These studies reveal a pivotal role for epigenetic regulation in mammalian sex determination, and provide new impetus for identifying additional causes of disorders of sex determination by environmental factors.
Project description:A critical transcription factor required for mammalian male sex determination is SRY (sex determining region on the Y chromosome). The expression of SRY in precursor Sertoli cells is one of the initial events in testis development. The current study was designed to determine the impact of environmentally induced epigenetic transgenerational inheritance on SRY during gonadal sex determination in the male. The agricultural fungicide vinclozolin and vehicle control (DMSO) exposed gestating females (F0 generation) during gonadal sex determination promoted the transgenerational inheritance of differential DNA methylation in sperm of the F3 generation (great grand-offspring). The fetal gonads in F3 generation males were used to identify potential alterations in SRY binding sites in the developing Sertoli cells. Chromatin immunoprecipitation with an SRY antibody followed by genome-wide promoter tiling array (ChIP-Chip) was used to identify alterations in SRY binding. A total of 81 adjacent oligonucleotide sites and 173 single oligo SRY binding sites were identified to be altered transgenerationally in the Sertoli cell vinclozolin lineage F3 generation males. Observations demonstrate the majority of the previously identified normal SRY binding sites were not altered and the altered SRY binding sites were novel and new additional sites. The chromosomal locations, gene associations and potentially modified cellular pathways were investigated. In summary, environmentally induces epigenetic transgenerational inheritance of germline epimutations appears to alter the cellular differentiation and development of the precursor Sertoli cell SRY binding during gonadal sex determination that influence the developmental origins of adult onset testis disease.
2015-08-28 | GSE72469 | GEO
Project description:Cryptobranchid sex determination
Project description:Purpose: In this study we employed unbiased, genome-wide techniques to identify regulatory elements during murine sex determination. Methods: We performed ATAC-seq on 60K FACS-purified XX and XY gonadal cells before and after sex determination to map nucleosome depleted regions (NDRs) indicative of regulatory elements. To determine whether these are active enhancers, we performed ChIP-seq for H3K27ac, a histone modification that marks active enhancers in both sexes and time points. Transient transgenics was performed on select enhancers to determine whether they are functional in gonads during the sex determination stage. Results: We have produced a genome wide map of potential regulatory elements and active enhancers during the process of murine sex determination. Furthermore, we validated the power of our dataset by identifying a novel enhancer downstream of Bmp2, a female-specific gene. Conclusions: This work supplies a powerful resource for identifying chromatin regulatory elements active during mammalian sex determination.
Project description:Environmental sex determination (ESD) occurs in divergent, phylogenetically unrelated taxa, and in some species co-occurs with genetic sex determination (GSD) mechanisms. Although epigenetic regulation in response to environmental effects has long been proposed to be associated with ESD, a systemic analysis on epigenetic regulation of ESD is still lacking. Using half-smooth tongue sole (Cynoglossus semilaevis) as a model – a marine fish which has both ZW chromosomal GSD and temperature-dependent ESD – we investigated the role of DNA methylation in transition from GSD to ESD by comparing gonadal DNA methylomes of parental females, parental pseudo-males, F1 females, F1 pseudo-males and normal males.
Project description:Transcriptomic changes following recent natural hybridization and allopolyploidy in the salt marsh species Spartina x townsendii and Spartina anglica (Poaceae) Allopolyploidy results from two events: the merger of divergent genomes and genome duplication. Both events have important functional consequences for the evolution and adaption of newly formed allopolyploid species. In spite of significant progress made the last years, a few studies have decoupled the effects of hybridization from genome duplication in the observed patterns of expression changes accompanying allopolyploidy in natural conditions. We used Agilent Rice oligo-microarrays to explore gene expression changes following allopolyploidy in Spartina that includes a classical example of recent allopolyploid speciation, S. anglica formed during the 19th century following genome duplication of the hybrid S. x townsendii. Our data indicate important, thought different effects of hybridization and genome duplication in the expression patterns of the hybrid and allopolyploid. Deviation from parental additivity was most important following hybridization and was accompanied by maternal expression dominance, although transgressively expressed genes were also encountered. Maternal dominance is attenuated following genome duplication in S. anglica while this species exhibits an increased number of transgressively over expressed genes. These results reflect the decoupled effects of the “genomic shock” following hybridization and genome redundancy, on the genetic, epigenetic and regulatory mechanisms characterizing transcriptomic evolution in allopolyploids.