Project description:We constructed a comparative proteome profile of female mouse fetal gonads at specific time points (11.5, 12.5, and 13.5 days post coitum), spanning a critical window for initiation of meiosis in female germ cells. We identified 3666 proteins, of which 473 were differentially expressed.
Project description:Here, we analyzed small RNA libraries derived from ovarian tissues heterozygous or mutant for the Tudor gene, Vreteno. In the absence of vret, Piwi-bound piRNAs are lost without changes in piRNA precursor transcript production, supporting a role for Vret in primary piRNA biogenesis. In the germline, piRNAs can engage in an Aub/Argonaute 3 (AGO3)-dependent amplification in the absence of Vret, suggesting that Vret function can distinguish between primary piRNAs loaded into Piwi/Aub complexes and piRNAs engaged in the amplification cycle. We propose that Vret acts at an early step in primary piRNA processing where it plays an essential role in transposon regulation. Keyword : Epigenetics 2 libraries were analyzed, with 1 being a control (heterozygote).
Project description:The initiation of meiotic division, proper homologous chromosome pairing, and recombination are essential for maintaining genome stability in gametes. Numerous genes are involved in regulating these key processes during meiosis. However, the role of gonad somatic cells in regulating the initiation and progression of germ cell meiosis remains poorly understood. In this study, we identify the Kitl/Kit signaling pathway as a critical regulator of meiotic in female gonads. Disruption of Kitl/Kit signaling, both in vivo and in vitro, impairs the initiation of meiosis and leads to abnormalities in meiotic progression. We also observed that the mTOR/S6 signaling pathway is inhibited when Kitl/Kit signaling is blocked. Notably, adding a mTOR activator to in vitro cultures of Kitl conditional knockout gonads partially rescued germ cell numbers and improved meiotic initiation efficiency. Our findings highlight the essential role of the Kitl-Kit-mTOR-S6 signaling axis in meiotic initiation and progression. This study reveals a novel function of Kitl/Kit signaling in regulating embryonic meiosis and provides a new framework for future research on how somatic cells influence germ cell meiosis.
Project description:We used the MPSS technology to uncover gene expression profiling in a greater depth in the early embryonic gonads and primordial germ cells (PGCs) in the chicken. Total numbers of sequenced signatures were 1,012,533 and 995,676 for the PGCs and gonad. Using a false discovery rate cut-off of 0.05, we found 3.05 % of all signatures in the PCGs and 1.89 % of all signatures in the gonad signatures were significantly up-regulated compared to each sample. The MPSS result was very consistent with our previous result using EST data(http://chickgce.snu.ac.kr/). Keywords: cell type comparison Experimental animals provided for this experiment were maintained at the University Animal Farm, Seoul National University, and all experimental procedures were performed at the affiliated laboratories of the university. Gonadal cells were retrieved from the gonads of 6.5-day-old (stage 29) White Leghorn (WL) embryos by our standard procedure [26]. Embryos were freed from the yolk by rinsing with calcium- and magnesium-free PBS and the gonads were retrieved by dissection of embryo abdomen with sharp tweezers under a stereomicroscope. Embryonic gonads were collected from total 1,947 embryos by 10 highly-skilled persons through 8 separated experimental batches. Gonadal tissues were dissociated by gentle pipetting in 0.05% (v:v) trypsin solution supplemented with 0.53 mM EDTA. After centrifuged at 200xg for 5 min, total gonadal cells were loaded into MACS (Miltenyi Biotech, Germany), and the separated primordial germ cells (PGCs) were immediately stored in liquid nitrogen (-190ºC) until processed further. The numbers of PGCs in cell population before and after loading were counted. MACS treatment for chicken PGCs and counting PGC number Chicken gonadal cells were incubated with PGC-specific primary antibody, anti-stage specific embryo antigen (anti-SSEA)-1 antibody for chicken PGCs (mouse IgM isotype), for 20 min at the room temperature of 20-25?C. Anti-SSEA-1 antibody developed by [27] was obtained from the Developmental Studies Hybridoma Bank developed under the auspices of the NICHD and maintained by the University of Iowa, Development of Biological Science. After washing with 1mL buffer (PBS supplement with 0.5% BSA and 2mM EDTA), the supernatant was completely removed. The pellet was mixed with 100 ? buffer containing 20? of rat anti-mouse IgM microbeads for 15 min at 4?C. Treated cells were carefully washed by the addition of 500 ? buffer and subsequently loaded with MACS.[28] For counting cell number, chicken PGCs before or after MACS treatment were fixed with 1% (v:v) glutaraldehyde for 5 min and rinsed with 1x PBS twice. The anti-SSEA-1 ascites fluid diluted 1:1,000 in PBS was added and subsequent steps were carried out using DAKO universal LSAB® kit, Peroxidase (DAKO, USA) according to the manufacturer’s instruction. After 8 batches of cell preparation, total cell number of PGC-enriched fraction and gonadal stromal cells was 5.26X106 and 1.76X108, respectively. These cell populations were further used for total RNA isolation and massively parallel signature sequencing (MPSS) analysis.