Project description:The genome of male germ cells is actively transcribed during spermatogenesis to produce phase-specific protein coding mRNAs and a considerable amount of different non-coding RNAs. Ribonucleoprotein (RNP) granule-mediated RNA regulation provides a powerful means to secure the quality and correct expression of the requisite transcripts. Haploid spermatids are characterized by a unique, unusually large cytoplasmic granule, the chromatoid body (CB), that emerges during the switch between the meiotic and post-meiotic phases of spermatogenesis. To better understand the role of the CB in male germ cell differentiation, we isolated CBs from mouse testes and revealed its full RNA and protein composition. We showed that the CB is mainly composed of RNA-binding proteins and other proteins involved RNA regulation. The CB was loaded with RNA, including pachytene piRNAs, a diverse set of mRNAs and a number of uncharacterized long non-coding transcripts. The CB was demonstrated to accumulate nascent RNA during all the steps of round spermatid differentiation. Our results revealed the CB as a large germ cell-specific RNP platform that is involved in the control of the highly complex transcriptome of haploid male germ cells. Transcriptome profling of purified chromatoid body, each steps of chromatoid body purification, and sortred round spermatid cells
Project description:The genome of male germ cells is actively transcribed during spermatogenesis to produce phase-specific protein coding mRNAs and a considerable amount of different non-coding RNAs. Ribonucleoprotein (RNP) granule-mediated RNA regulation provides a powerful means to secure the quality and correct expression of the requisite transcripts. Haploid spermatids are characterized by a unique, unusually large cytoplasmic granule, the chromatoid body (CB), that emerges during the switch between the meiotic and post-meiotic phases of spermatogenesis. To better understand the role of the CB in male germ cell differentiation, we isolated CBs from mouse testes and revealed its full RNA and protein composition. We showed that the CB is mainly composed of RNA-binding proteins and other proteins involved RNA regulation. The CB was loaded with RNA, including pachytene piRNAs, a diverse set of mRNAs and a number of uncharacterized long non-coding transcripts. The CB was demonstrated to accumulate nascent RNA during all the steps of round spermatid differentiation. Our results revealed the CB as a large germ cell -specific RNP platform that is involved in the control of the highly complex transcriptome of haploid male germ cells. Small RNA profiling of purified chromatoid body, each steps of chromatoid body purification, and sortred round spermatid cells
Project description:Post-transcriptional regulatory mechanisms are crucial for protein synthesis during spermatogenesis and often organized by the chromatoid body. Chromatoid bodies are large cytoplasmic ribonucleoprotein granules, whose precise function and composition remain unclear. Here, we identify NSun2 as a novel component of the chromatoid body, and further show that this RNA methylase is essential for germ cell differentiation in the mouse testis. Lack of NSun2 leads to down-regulation of genes controlling RNA processing and post-transcriptional repression pathways, including Ddx4, Mili, Piwil1 (Miwi) and Tudor domain containing (Tdrd) proteins. Germ cell differentiation was blocked specifically at the pachytene stage by lack of NSun2, as spermatogonial and Sertoli cells were unaffected in knockout mice. We observed the same phenotype when we simultaneously deleted NSun2 with Dnmt2, the only other characterized cytosine-5 RNA methyltransferase to date, indicating that Dnmt2 was not functionally redundant for NSun2 in spermatogonial stem cells or Sertoli cells. Thus, our data indicate that RNA methylation pathways play an essential role in male germ cell differentiation.
Project description:Post-transcriptional regulatory mechanisms are crucial for protein synthesis during spermatogenesis and often organized by the chromatoid body. Chromatoid bodies are large cytoplasmic ribonucleoprotein granules, whose precise function and composition remain unclear. Here, we identify NSun2 as a novel component of the chromatoid body, and further show that this RNA methylase is essential for germ cell differentiation in the mouse testis. Lack of NSun2 leads to down-regulation of genes controlling RNA processing and post-transcriptional repression pathways, including Ddx4, Mili, Piwil1 (Miwi) and Tudor domain containing (Tdrd) proteins. Germ cell differentiation was blocked specifically at the pachytene stage by lack of NSun2, as spermatogonial and Sertoli cells were unaffected in knockout mice. We observed the same phenotype when we simultaneously deleted NSun2 with Dnmt2, the only other characterized cytosine-5 RNA methyltransferase to date, indicating that Dnmt2 was not functionally redundant for NSun2 in spermatogonial stem cells or Sertoli cells. Thus, our data indicate that RNA methylation pathways play an essential role in male germ cell differentiation. Four sample groups: Testes from Wild-type and NSun2 knock out mice at 15 and 49 days; 6 samples in each group
Project description:Nonsense-mediated RNA decay (NMD) is a highly conserved and selective RNA turnover pathway that depends on the endonuclease SMG6. Here, we show that SMG6 is essential for male germ cell differentiation in mice. Germ-cell conditional knockout (cKO) of Smg6 induces extensive transcriptome misregulation, including a failure to eliminate meiotically expressed transcripts in early haploid cells, and accumulation of NMD target mRNAs with long 3’ untranslated regions (UTRs). Loss of SMG6 in the male germline results in complete arrest of spermatogenesis at the early haploid cell stage. We find that SMG6 is strikingly enriched in the chromatoid body (CB), a specialized cytoplasmic granule in male germ cells also harboring PIWI-interacting RNAs (piRNAs) and the piRNA-binding protein PIWIL1.
Project description:The ciliary body is required for the maintenance of intraocular pressure and immunity as well as vision accommodation. We report a comprehensive cell atlas of human ciliary body from single-cell RNA sequencing (scRNAseq)
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of fluorescent activated cell sorting (FACS) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in FACS isolated components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. Keywords: Comparison of kidney components. At different developmental time points we isolate discrete elements of the kidney by using fluorescent activated cell sorting (FACS) and then define their gene expression profiles with microarrays.