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:Maintenance and maturation of primordial germ cells is controlled by complex genetic and epigenetic cascades, and disturbances in this network lead to either infertility or malignant aberration. Transcription factor Tcfap2c / TFAP2C has been described to be essential for primordial germ cell maintenance and to be upregulated in several human germ cell cancers. Using global gene expression profiling, we identified genes deregulated upon loss of Tcfap2c in primordial germ cell-like cells. We show that loss of Tcfap2c affects many aspects of the genetic network regulating germ cell biology, such as downregulation maturation markers and induction of markers indicative of somatic differentiation, cell cycle, epigenetic remodeling, and pluripotency associated genes. Chromatin-immunoprecipitation analyses demonstrated binding of Tcfap2c to regulatory regions of deregulated genes (Sfrp1, Dmrt1, Nanos3, c-Kit, Cdk6, Cdkn1a, Fgf4, Klf4, Dnmt3b and Dnmt3l) suggesting that these genes are direct transcriptional targets of Tcfap2c in primordial germ cells. Since Tcfap2c deficient primordial germ cell like cells display cancer related deregulations in epigenetic remodeling, cell cycle and pluripotency control, the Tcfap2c-knockout allele was bred onto 129S2/Sv genetic background. There, mice heterozygous for Tcfap2c develop germ cell cancer with high incidence. Precursor lesions can be observed as early as E16.5 in developing testes displaying persisting expression of pluripotency markers. We further demonstrate, that mice with a heterozygous deletion of the Tcfap2c target gene Nanos3 are also prone to develop teratoma. These data highlight Tcfap2c as a critical and dose-sensitive regulator of germ cell fate. 8 samples were analyzed. Ctrl ESC: Control mouse embryonic stem cells (ESCs), 2 biological rep KO ESC: Tcfap2c knock-out mouse embryonic stem cells (ESCs), 2 biological rep Ctrl PGC: Control mouse primordial germ cells (PGCs), 2 biological rep KO PGC: Tcfap2c knock-out mouse primordial germ cells (PGCs), 2 biological rep
Project description:The primordial follicle pool established during the perinatal period, serves as the lifelong source of oocytes, with its depletion leading to premature ovarian failure (POF). Germ cell development from primordial germ cells (PGCs) to primordial follicle formation is tightly regulated by transcription and extensive post-transcriptional alternative splicing (AS). However, the dynamics and role of AS during PGC development and follicle formation remains poorly understood. Analysis of single-cell transcriptomes from E14.5 to P5 mouse ovaries revealed dynamic AS changes and key splicing factors involved in primordial follicle formation. Here, we employed a conditional knockout (cKO) model to demonstrate that hnRNPL loss in pre-meiotic germ cells disrupts homologous synapsis, induces extensive DNA damage, and results in abnormal diplotene-stage germ cells. Further analysis revealed that hnRNPL deficiency reduces transcript levels of genes essential for primordial follicle maintenance, causes aberrant splicing and protein expression of synapsis-related genes. These cumulative effects culminate in POF and infertility. Our findings explore AS dynamics and highlight hnRNPL as a key regulator of AS in primordial follicle pool formation and activation.
Project description:X chromosome reactivation (XCR) occurs over a prolonged period during genome-wide reprogramming in female germ cells, initiating soon after primordial germ cell specification. The kinetics of XCRs remain poorly understood, as previous studies of XCR were based on a few genes. For a global appraisal of XCR dynamics, we performed single-cell RNA-seq on F1 female (XX(Xist∆)) and male (XY) germ cells from E9.5 to E16.5 stages in development. Through the incorporation of interspecific crosses between C57B6J (B6) and Castaneus (CAST) parental mouse strains, containing a high number of informative single-nucleotide variants, we are able to distinguish gene expression from parental chromosomes in F1 embryos computationally.