Project description:The cascade of molecular events involved in mammalian sex determination has been shown to involve the SRY gene, but specific downstream events have eluded researchers for decades. The current study identifies one of the first direct downstream targets of the male sex-determining factor SRY as the basic-helix-loop-helix (bHLH) transcription factor TCF21. SRY was found to directly associate with the Tcf21 promoter SRY/SOX9 response element both in vitro and in vivo during male sex determination. TCF21 was found to promote an in vitro sex reversal of embryonic ovarian cells to promote precursor Sertoli cell differentiation. Therefore, SRY acts directly on the Tcf21 promoter to, in part, initiate a cascade of events associated with Sertoli cell differentiation and embryonic testis development. We used microarrays to determine genes whose expression was stimulated in rat E13 ovarian cell sub-cultures in the presence of a pCMV-myc-expression plasmid over-expressing the Sry, Tsf21, and/or Tcf12 (Reb-alfa) genes. RNA samples from the control group (untreated E13 rat ovarian cells) are compared to RNA from 4 groups of treated E13 rat ovarian cells: 1) Sry overexpressing, 2) Tcf21 overexpressing, 3) Tcf12 (Reb alfa) overexpressing, and 4) Tcf21 + Tcf12 (Reb-alfa) overexpressing. Untreated E13 testis cell sub-cultures were also analyzed. 3 biological replicates each group.
Project description:A major event in mammalian male sex determination is the induction of the testis determining factor Sry and its downstream gene Sox9. The current study provides one of the first genome wide analyses of the downstream gene binding targets for SRY and SOX9 to help elucidate the molecular control of Sertoli cell differentiation and testis development. A modified ChIP-Chip analysis using a comparative hybridization was used to identify 71 direct downstream binding targets for SRY and 109 binding targets for SOX9. Interestingly, only 5 gene targets overlapped between SRY and SOX9. In addition to the direct response element binding gene targets, a large number of atypical binding gene targets were identified for both SRY and SOX9. Bioinformatic analysis of the downstream binding targets identified gene networks and cellular pathways potentially involved in the induction of Sertoli cell differentiation and testis development. The specific DNA sequence binding site motifs for both SRY and SOX9 were identified. Observations provide insights into the molecular control of male gonadal sex determination. The current study provides one of the first genome wide analyses of the downstream gene binding targets for SRY and SOX9 to help elucidate the molecular control of Sertoli cell differentiation and testis development. At embryonic day 13 (E13) of pregnancy rats were euthanized and embryonic gonads were collected for chromatin. A modified ChIP-Chip analysis using a comparative hybridization was used to identify direct downstream binding targets for SRY and for SOX9. Then, bioinformatic analysis of the downstream binding targets was done to identify gene networks and cellular pathways that are potentially involved in the induction of Sertoli cell differentiation and testis development.
Project description:A major event in mammalian male sex determination is the induction of the testis determining factor Sry and its downstream gene Sox9. The current study provides one of the first genome wide analyses of the downstream gene binding targets for SRY and SOX9 to help elucidate the molecular control of Sertoli cell differentiation and testis development. A modified ChIP-Chip analysis using a comparative hybridization was used to identify 71 direct downstream binding targets for SRY and 109 binding targets for SOX9. Interestingly, only 5 gene targets overlapped between SRY and SOX9. In addition to the direct response element binding gene targets, a large number of atypical binding gene targets were identified for both SRY and SOX9. Bioinformatic analysis of the downstream binding targets identified gene networks and cellular pathways potentially involved in the induction of Sertoli cell differentiation and testis development. The specific DNA sequence binding site motifs for both SRY and SOX9 were identified. Observations provide insights into the molecular control of male gonadal sex determination. The current study provides one of the first genome wide analyses of the downstream gene binding targets for SRY and SOX9 to help elucidate the molecular control of Sertoli cell differentiation and testis development. At embryonic day 13 (E13) of pregnancy rats were euthanized and embryonic gonads were collected for chromatin. A modified ChIP-Chip analysis using a comparative hybridization was used to identify direct downstream binding targets for SRY and for SOX9. Then, bioinformatic analysis of the downstream binding targets was done to identify gene networks and cellular pathways that are potentially involved in the induction of Sertoli cell differentiation and testis development.
Project description:A major event in mammalian male sex determination is the induction of the testis determining factor Sry and its downstream gene Sox9. The current study provides one of the first genome wide analyses of the downstream gene binding targets for SRY and SOX9 to help elucidate the molecular control of Sertoli cell differentiation and testis development. A modified ChIP-Chip analysis using a comparative hybridization was used to identify 71 direct downstream binding targets for SRY and 109 binding targets for SOX9. Interestingly, only 5 gene targets overlapped between SRY and SOX9. In addition to the direct response element binding gene targets, a large number of atypical binding gene targets were identified for both SRY and SOX9. Bioinformatic analysis of the downstream binding targets identified gene networks and cellular pathways potentially involved in the induction of Sertoli cell differentiation and testis development. The specific DNA sequence binding site motifs for both SRY and SOX9 were identified. Observations provide insights into the molecular control of male gonadal sex determination.
Project description:A major event in mammalian male sex determination is the induction of the testis determining factor Sry and its downstream gene Sox9. The current study provides one of the first genome wide analyses of the downstream gene binding targets for SRY and SOX9 to help elucidate the molecular control of Sertoli cell differentiation and testis development. A modified ChIP-Chip analysis using a comparative hybridization was used to identify 71 direct downstream binding targets for SRY and 109 binding targets for SOX9. Interestingly, only 5 gene targets overlapped between SRY and SOX9. In addition to the direct response element binding gene targets, a large number of atypical binding gene targets were identified for both SRY and SOX9. Bioinformatic analysis of the downstream binding targets identified gene networks and cellular pathways potentially involved in the induction of Sertoli cell differentiation and testis development. The specific DNA sequence binding site motifs for both SRY and SOX9 were identified. Observations provide insights into the molecular control of male gonadal sex determination.
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.
Project description:The cascade of molecular events involved in mammalian sex determination has been shown to involve the SRY gene, but specific downstream events have eluded researchers for decades. The current study identifies one of the first direct downstream targets of the male sex-determining factor SRY as the basic-helix-loop-helix (bHLH) transcription factor TCF21. SRY was found to directly associate with the Tcf21 promoter SRY/SOX9 response element both in vitro and in vivo during male sex determination. TCF21 was found to promote an in vitro sex reversal of embryonic ovarian cells to promote precursor Sertoli cell differentiation. Therefore, SRY acts directly on the Tcf21 promoter to, in part, initiate a cascade of events associated with Sertoli cell differentiation and embryonic testis development.
Project description:In mammals, sex determination depends on the paternal transmission of the Y chromosome, which bears the Sry gene. At the time of sex determination, Sry becomes up-regulated in XY gonads initiating the expression of various factors required for testicular development. Most of these factors remain to be identified. As a consequence, the genetic causes of gonadal dysgenesis in human patients, other than those involving SRY, remain unknown. We found that Nrg1 is a new gene involved in early testicular development. To study the role of Nrg1 in embryonic testicular differentiation, conditional inactivation of Nrg1 was achieved with the help of a Wt1-Cre line. Mutant mice show defects of testis development. In order to correlate the defects of cellular processes and the misregulated gene network(s), expression profiles were examined in controls and mutants testes at 13.5 dpc. Each testis sample was pooled from eight embryos.
Project description:The deletion of a single miRNA cluster, miR-17~92, is sufficient to induce primary sex reversal in XY mice. The expression of the testis determining gene, Sry, is delayed in embryonic XY miR-17~92 knockout gonads, which immediately activate the ovarian genetic program. Single cell RNA-seq analysis shows that Sertoli cell differentiation is highly reduced, delayed and unable to trigger testis differentiation. Consistent with the well-known role of miRNAs in gene regulation, the expression of target genes of miR-17~92 is not stabilized in XY mutant gonads at E11.5, affecting, in turn, the fine regulation of large gene networks involved in mammalian sex determination. Our results reveal that the miR-17~92 cluster is a novel sex-determining factor that modulates several gene networks required for accurate timing of Sry expression and Sertoli cell differentiation during testis determination and early differentiation.
Project description:Sry is sufficient to induce testis formation and subsequent male development of internal and external genitalia in chromosomally female mice and humans. In XX sex-reversed males such as XX/Sry-transgenic (XX/Sry) mice, however, testicular germ cells always disappear soon after birth due to germ cell autonomous defects. Therefore, it remains unclear whether or not Sry alone is sufficient to induce a fully functional testicular soma capable of supporting complete spermatogenesis in the XX body. Here we demonstrated that the testicular somatic environment of XX/Sry males is defective in the later phases of spermatogenesis. Spermatogonial transplantation analyses using XX/Sry male mice revealed that donor XY spermatogonia are capable of proliferating, entering meiosis and differentiating into the round spermatid stage. XY donor-derived round spermatids, however, were frequently detached from the XX/Sry seminiferous epithelia and underwent cell death, thereby preventing further progress beyond the elongated spermatid stage. In contrast, immature XY seminiferous tubule segments transplanted under XX/Sry testis capsules clearly displayed proper differentiation into elongated spermatids in the transplanted XY donor tubules. Microarray analysis of seminiferous tubules isolated from XX/Sry testes confirmed missing expression of several Y-linked genes and alterations in the expression profile of genes associated with spermatogenesis. Therefore, our findings indicate dysfunction of the somatic tubule components, probably Sertoli cells, of XX/Sry testes, supporting our hypothesis that Sry alone is insufficient to induce a fully functional Sertoli cell in XX mice. Keywords: comparative genomic hybridization