Single cell microarray analysis of mouse primordial germ cells with Prdm14 mutation.
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ABSTRACT: Prdm14 is a critical gene for specifying mouse primordial germ cells (PGCs). The changes in expression in mouse PGCs caused by mutations of the Prdm14 gene were investigated at the single-cell level using microarray analysis.
Project description:PRDM14 is a crucial regulator of mouse primordial germ cells (mPGC), epigenetic reprogramming and pluripotency, but its role in the evolutionarily divergent regulatory network of human PGCs (hPGCs) remains unclear. Besides, a previous knockdown study indicated that PRDM14 might be dispensable for human germ cell fate. Here, we decided to use inducible degrons for a more rapid and comprehensive PRDM14 depletion. We show that PRDM14 loss results in significantly reduced specification efficiency and an aberrant transcriptome of human PGC-like cells (hPGCLCs) obtained in vitro from human embryonic stem cells (hESCs). Chromatin immunoprecipitation and transcriptomic analyses suggest that PRDM14 cooperates with TFAP2C and BLIMP1 to upregulate germ cell and pluripotency genes, while repressing WNT signalling and somatic markers. Notably, PRDM14 targets are not conserved between mouse and human, emphasising the divergent molecular mechanisms of PGC specification. The effectiveness of degrons for acute protein depletion is widely applicable in various developmental contexts.
Project description:PRDM14 is a crucial regulator of mouse primordial germ cells (mPGC), epigenetic reprogramming and pluripotency, but its role in the evolutionarily divergent regulatory network of human PGCs (hPGCs) remains unclear. Besides, a previous knockdown study indicated that PRDM14 might be dispensable for human germ cell fate. Here, we decided to use inducible degrons for a more rapid and comprehensive PRDM14 depletion. We show that PRDM14 loss results in significantly reduced specification efficiency and an aberrant transcriptome of human PGC-like cells (hPGCLCs) obtained in vitro from human embryonic stem cells (hESCs). Chromatin immunoprecipitation and transcriptomic analyses suggest that PRDM14 cooperates with TFAP2C and BLIMP1 to upregulate germ cell and pluripotency genes, while repressing WNT signalling and somatic markers. Notably, PRDM14 targets are not conserved between mouse and human, emphasising the divergent molecular mechanisms of PGC specification. The effectiveness of degrons for acute protein depletion is widely applicable in various developmental contexts.
Project description:In mammals, sex differentiation of primordial germ cells (PGCs) is determined by extrinsic cues from the environment1. In female PGCs, expression of Stimulated by retinoic acid 8 (Stra8) and meiosis are induced in response to retinoic acid (RA) provided by the mesonephroi2-4. Given the widespread role of RA signaling during development8,9, the molecular mechanism specifying the competence of PGCs to timely express Stra8 and enter meiosis are unknown2,10. Here we identify gene dosage dependent roles in PGC development for Ring1 and Rnf2, two central components of the Polycomb Repressive Complex 1 (PRC1)11,13. Both paralogs are essential for PGC development between day 10.5 and 11.5 of gestation. Rnf2 is subsequently required in female PGCs for maintaining high levels of Oct4 and Nanog expression6, and for preventing premature induction of meiotic gene expression and entry into meiotic prophase. Chemical inhibition of RA signaling partially suppresses precocious Oct4 down-regulation and Stra8 activation in Rnf2-deficient female PGCs. Chromatin immunoprecipitation analyses show that Stra8 is a direct target of PRC1 and PRC2 in PGCs. These data demonstrate the importance of PRC1 gene dosage in PGC development and in coordinating the timing of sex differentiation of female PGCs by antagonizing extrinsic RA signaling. Gene expression of mouse primordial germ cells was analysed using Affymetrix microarray. Primodial germ cells were purified from embryos carrying Oct4(deltaPE)-GFP transgene by FACS.
Project description:Gene regulatory networks underlying cellular pluripotency are controlled by a core circuitry of transcription factors, including POU5F1 and NANOG in mammals. However, the evolutionary origin and transformation of pluripotency transcriptional networks have not been elucidated in deuterostomes. PR domain-containing protein 14 (PRDM14) is specifically expressed in pluripotent cells and germ cells, and is required for establishing embryonic stem cells (ESCs) and primordial germ cells (PGCs) in mice. Here, we compared the functions and expression patterns of PRDM14 orthologues within deuterostomes. Amphioxus PRDM14, zebrafish PRDM14, and the combination of sea urchin PRDM14 and CBFA2T compensated for disruption of the mouse Prdm14 gene in terms of maintaining mouse ESC pluripotency. Interestingly, Prdm14 was expressed in motor neurons, but not in germ cells in amphioxus embryos as observed in zebrafish embryos. Therefore, our results suggest that the integration of the PRDM14–CBFA2T complex into the transcriptional network for pluripotency may be essential for stabilizing pluripotency during the early amniote development.
Project description:In mammals, sex differentiation of primordial germ cells (PGCs) is determined by extrinsic cues from the environment1. In female PGCs, expression of Stimulated by retinoic acid 8 (Stra8) and meiosis are induced in response to retinoic acid (RA) provided by the mesonephroi2-4. Given the widespread role of RA signaling during development8,9, the molecular mechanism specifying the competence of PGCs to timely express Stra8 and enter meiosis are unknown2,10. Here we identify gene dosage dependent roles in PGC development for Ring1 and Rnf2, two central components of the Polycomb Repressive Complex 1 (PRC1)11,13. Both paralogs are essential for PGC development between day 10.5 and 11.5 of gestation. Rnf2 is subsequently required in female PGCs for maintaining high levels of Oct4 and Nanog expression6, and for preventing premature induction of meiotic gene expression and entry into meiotic prophase. Chemical inhibition of RA signaling partially suppresses precocious Oct4 down-regulation and Stra8 activation in Rnf2-deficient female PGCs. Chromatin immunoprecipitation analyses show that Stra8 is a direct target of PRC1 and PRC2 in PGCs. These data demonstrate the importance of PRC1 gene dosage in PGC development and in coordinating the timing of sex differentiation of female PGCs by antagonizing extrinsic RA signaling. Gene expression of mouse primordial germ cells was analysed using RNAseq method. Primodial germ cells were purified from embryos carrying Oct4(-delta-PE)-GFP transgene by FACS.
Project description:Primordial germ cells (PGCs), the embryonic precursors of eggs and sperm, are a unique model for identifying and studying regulatory mechanisms in singly migrating cells. From their time of specification to eventual colonization of the gonad, mouse PGCs traverse through and interact with many different cell types, including epithelial cells and mesenchymal tissues. Work in drosophila and zebrafish have identified many genes and signaling pathways involved in PGC migration, but little is known about this process in mammals. We have generated a point mutation in the Ror2 gene that we know disrupts primordial germ cell migration in the developing mouse embryo. We used microarray analysis to determine if this defect is mediated through genome-wide or pathway-specific transcriptional changes. We analyzed primordial germ cells (PGCs) from 4 wild-type (WT) and 4 Ror2Y324C/Y324C mutant embryos using Oct4-DPE-EGFP. PGCs were collected during their active migratory state at embryonic day 9.5 (somite range 20-25).
Project description:In poultry, in vitro derived primordial germ cells (PGCs) represent an important tool for management of genetic resources. However, several studies have highlighted sexual differences exhibited by PGCs through in vitro steps, which may compromise their reproductive capacities. To understand this phenomenon, we compared the proteome of pregonadal chicken male (ZZ) and female (ZW) PGCs expanded in vitro by quantitative proteomic analysis using a GeLC-MS/MS strategy. The proteins found to be differentially abundant in chicken male and female PGCs indicated their early sexual identity. Many of the proteins up-accumulated in male PGCs were encoded by genes strongly enriched in the sexual chromosome Z. This suggests that the known lack of dosage compensation of the transcription of Z-linked genes between sexes persists at protein level in PGCs, and that this may be a key factor of their autonomous sex differentiation. Male and female PGCs up-accumulated protein sets were associated with differential biological processes, and contained proteins biologically relevant for male and female germ cell development respectively. This study presents first evidence on early predetermined sex specific cell fate of chicken PGCs that will help to understand their sexual physiological specificities and enable more precise sex-specific adaptation of in vitro culture conditions.
Project description:MCM8 has emerged as a core gene in reproductive aging and is crucial for meiotic homologous recombination repair. It also safeguards genome stability by coordinating the replication stress response during mitosis, but its function in mitotic germ cells remains elusive. Here we found that the number of primordial germ cells (PGCs) decreased dramatically after MCM8 deficiency due to proliferation defects. We further demonstrated that MCM8 interacted with two known helicases DDX5 and DHX9 in PGCs, and loss of MCM8 led to R-loop accumulation by reducing the retention of these helicases at R-loops, thus inducing genome instability. Cells expressing premature ovarian insufficiency-causative mutants of MCM8 with decreased interaction with DDX5 displayed increased R-loop levels. These results suggest that MCM8 interacts with R-loop-resolving factors to prevent DNA damage in PGCs, thus maintaining PGC proliferation and establishing the reproductive reserve. Our findings thus reveal a novel role for MCM8 in PGC development and improve our understanding of reproductive aging caused by genome instability in mitotic germ cells.
Project description:Primordial germ cells (PGCs) are precursors of both male and female gametes as fundamental materials for organism development. The transcriptome, methylome and chromatin accessibility profiles of PGCs in both mice and humans have been recently reported. However, little is known about the characteristics of PGCs at the protein levels, which directly exert cellular functions. Here, we construct landscapes of both proteome of mouse PGCs at E11.5, E13.5 and E16.5 days, the three critical developmental windows for PGCs’ sex differentiation, female meiosis initiation and male mitotic arrest. In each developmental stage of PGCs nearly 2000-3000 proteins are identified, among which specific functional pathways such as oxidative phosphorylation, DNA damage repair, and meiotic cell cycle are involved for different events during PGCs development. Thus, our work offers a valuable resource for the systematic investigations of PGC development at protein level.