Project description:MicroRNAs (miRNAs) are a highly conserved class of small RNAs which function in a sequence-specific manner to post-transcriptionally regulate expression of target genes. Tissue-specific miRNA expression studies have discovered numerous functions for miRNAs in various aspects of embryonic development, but a role for miRNAs in gonadal development and sex differentiation has not yet been reported. Using the chicken embryo as a vertebrate model, differential miRNA expression between male and female embryonic gonads, was analysed at three developmental stages (embryonic days (E) 5.5, E6.5 and E9.5), using custom-designed 4x2K CombiMatrix miRNA microarray. The aims of this study were to: 1-identify miRNAs differentialy expressed by sex; 2-identify sex-specific miRNAs; 3-analyse global changes in miRNA up-regulation in male versus female gonads before, during and after the histological onset of sexual differentiation. This study provides a basis for establishing whetehr miRNAs are involved in either initiating or regulating vertebrate gonadal sex differentiation. Keywords: miRNA, sex comparison, developmental stage comparison.
Project description:Following sex determination, XY and XX gonads develop into a testis and an ovary, respectively. Depending on the sex of the gonad, resident germ cells will subsequently be committed to either spermatogenesis or oogenesis. In this study we took advantage of the Wv/Wv mouse genetic model, in which gonads are almost devoided of germ cells, to uncover gene expression underlying fetal germ cell development.
Project description:Gonadal sex determining (GSD) genes that initiate fetal ovarian and testicular development and differentiation are expressed in the cells of the urogenital ridge that differentiate as somatic support cells (SSCs), i.e., granulosa cells of the ovary and Sertoli cells of the testis. To identify potential new mammalian GSD genes, we analyzed the gene expression differences between XX and XY SSCs cells isolated from the gonads of embryonic day (E) 13 mouse fetuses carrying an EGFP reporter transgene expressed specifically in SSCs. In addition, genome wide expression differences between XX and XY E13 whole gonads were examined. Newly identified differentially expressed transcripts are potential GSD genes involved in unexplained human sex reversal cases. Keywords: microarray, mouse fetal gonadal somatic support cells, sex determination
Project description:MicroRNAs (miRNAs) are a highly conserved class of small RNAs which function in a sequence-specific manner to post-transcriptionally regulate expression of target genes. Tissue-specific miRNA expression studies have discovered numerous functions for miRNAs in various aspects of embryonic development, but a role for miRNAs in gonadal development and sex differentiation has not yet been reported. Using the chicken embryo as a vertebrate model, differential miRNA expression between male and female embryonic gonads, was analysed at three developmental stages (embryonic days (E) 5.5, E6.5 and E9.5), using custom-designed 4x2K CombiMatrix miRNA microarray. The aims of this study were to: 1-identify miRNAs differentialy expressed by sex; 2-identify sex-specific miRNAs; 3-analyse global changes in miRNA up-regulation in male versus female gonads before, during and after the histological onset of sexual differentiation. This study provides a basis for establishing whetehr miRNAs are involved in either initiating or regulating vertebrate gonadal sex differentiation. Keywords: miRNA, sex comparison, developmental stage comparison. miRNA samples from male and female embryonic chicken gonads from three developmental stages: embryonic day (E) 5.5 (Hamilton & Hamburger (HH) stage 27-28), E6.5 (HH stage 29-30) & E9.5 (HH stage 35-36). Samples are listed with biological replicates used for analysis in brackets following: 1 - Male E5.5 (5); 2 - Female E5.5 (4); 3 - Male E6.5 (5); 4 - Female E6.5 (3); 5 - Male E9.5 (4); 6 - Female E9.5 (4).
Project description:Sex determination in the honeybee (Apis mellifera) is governed by the queen-controlled unfertilization or fertilization of embryo, though the mechanisms of determination are poorly understood. Here, we obtained the transcriptomes from individual worker and drone embryo during the embryonic development (day 1 to day 3). We show that transcriptional difference between worker and drone embryo is very small during the first day of hatching, during which sex-determinant gene csd expresses similarly. Differential transcription between worker and drone embryo bursts at day 2, among which csd is induced in worker embryo at day 2 and sex-lethal gene sxl is repressed in male embryo. An unexpected global regulation of alternative splicing accompanies the honeybee embryonic development, and male and worker embryo show distinct regulatory patterns and mechanisms. This study suggests the honeybee sex determination is more globally controlled at both the transcriptional and alternative splicing levels.
Project description:Avian sex is determined by various factors, such as the dosage of DMRT1 and cell-autonomous mechanisms. While the sex-determination mechanism in gonads is well analyzed, the mechanism in germ cells remains unclear. In this study, we explored the gene expression profiles of male and female primordial germ cells (PGCs) during embryogenesis in chickens to predict the mechanism of sex-determination. Male and female PGCs were isolated from blood and gonads with a purity > 96% using flow cytometry and analyzed using RNA-seq. Prior to settlement in the gonads, female circulating PGCs (cPGCs) obtained from blood displayed sex-biased expression. Gonadal PGCs (gPGCs) also displayed sex-biased expression, and the number of female-biased genes detected was higher than male-biased genes. The female-biased genes in gPGCs were enriched in some metabolic processes. To reveal the mechanisms underlying the transcriptional regulation of female-biased genes in gPGCs, we performed stimulation tests. Stimulation with retinoic acid against cultured gPGCs derived from male embryos resulted in the upregulation of several female-biased genes. Overall, our results suggest that sex determination of avian PGCs possess aspects of both cell-autonomous and somatic cell regulation. Moreover, it appears that sex determination occurs earlier in females than in males.
Project description:Following sex determination, XY and XX gonads develop into a testis and an ovary, respectively. Depending on the sex of the gonad, resident germ cells will subsequently be committed to either spermatogenesis or oogenesis. In this study we took advantage of the Wv/Wv mouse genetic model, in which gonads are almost devoided of germ cells, to uncover gene expression underlying fetal germ cell development. Male and Female gonads were collected at 12, 14 and 16 days post coitum (dpc) from wild-type and Wv/Wv mouse embryos. Total RNAs were extracted and hybridized on Affymetrix microarrays. Expression signals from male and female gonads or from wild-type and mutant gonads were compared to identify sexually dimorphic genes as well as genes expressed in germ cell during fetal gonad development.