Project description:SETX is a DNA/RNA helicase that resolves R-loop, and lack of SETX in germ cells causes meiotic arrest. To investigate roles of SETX in transcription during meiosis, we perfomred ChIP-seq of SETX using antibodies.
Project description:SETX is a DNA/RNA helicase that resolves R-loop, and lack of SETX in germ cells causes meiotic arrest. To investigate roles of SETX in transcription during meiosis, we perfomred CUT&Tag of SETX and R-loops using antibodies against them.
Project description:Male germ cells establish a unique heterochromatin domain, the XY-body, early in meiosis. How this domain is maintained through the end of meiosis and into post-meiotic germ cell differentiation is poorly understood. ADAD2 is a late meiotic male germ cell specific RNA binding protein, loss of which leads to post-meiotic germ cell defects. Analysis of ribosome association in Adad2 mutants revealed defective translation of Mdc1, a key regulator of XY-body formation, late in meiosis. As a result, Adad2 mutants show normal establishment but failed maintenance of the XY-body. Observed XY-body defects are concurrent with abnormal autosomal heterochromatin and ultimately lead to severely perturbed post-meiotic germ cell heterochromatin and cell death. These findings highlight the requirement of ADAD2 for Mdc1 translation, the role of MDC1 in maintaining meiotic male germ cell heterochromatin, and the importance of late meiotic heterochromatin for normal post-meiotic germ cell differentiation.
Project description:The limited number of in vivo germ cells poses an impediment to genome-wide studies. Here, we applied a small-scale ChIP-Seq method on purified mouse fetal germ cells to generate genome-wide maps of four histone modifications (H3K4me3, H3K27me3, H3K27ac and H2BK20ac), facilitating the identification of active and repressed cis-regulatory elements in germ cells in vivo. Comparison of active chromatin state between somatic, embryonic stem cells (ESC) and germ cells revealed promoters and enhancers needed for stem cell maintenance and germ cell development. The nuclear receptor Nr5a2 motif is enriched at a subset of cis-regulatory regions and we confirm its role in germ cell differentiation. Interestingly, germ cells have comparatively more H3K27me3-marked sites that are absent in ESC and other somatic cell types. These repressed regions are enriched for retrotransposons and MHC genes and this indicates that these loci are specifically silenced in germ cells. Together, our study provides the first genome-wide histone modification maps of in vivo germ cells and revealed the molecular chromatin signatures unique to germ cells. Germ cells were FACS-purified from gonadal single cell suspension based on Pou5f1-GFP expression. ChIP-seq of Histone modification was done for two timepoints in this study: E11.5 (male/female), E13.5 (male). For E13.5 timepoint, two biological replicates were analyzed. In order to validate small scale ChIP-seq method limited number of ES cells were used to check consistency of ChIP-seq data.
Project description:The innate immune response is the first line of defense against pathogens, and factors that control this cellular response represent targets for treating both infectious and inflammatory diseases. Here, we reveal a novel role for the human helicase SETX, also previously implicated in amyotrophic lateral sclerosis (ALS4) and ataxia with oculomotor apraxia (AOA2), in controlling the magnitude of the antiviral response. Cells depleted for SETX and AOA2 patient-derived SETX-null cells show increased expression of antiviral mediators in response to infection. Mechanistically, this effect is achieved through SETX-mediated inhibition of RNAPII transcription of antiviral genes, and depends on SETX helicase activity. Our results suggest that SETX helps maintain the delicate balance between controlling viral infection and avoiding the potentially detrimental effects of an excessive antiviral response. More broadly, the observation that SETX can regulate the transcriptional activity of specific genes may have important implications for disorders where SETX function is compromised.
Project description:During spermatogenesis, mammalian spermatogonia undergo mitotic division, to maintain stem cell pool via self-renewal and generate differentiating progenitor cells for entry into meiotic prophase. During the perinatal stage, de novo DNA methylation occurring in pro-spermatogonia plays a key role to complete meiotic prophase and initiate meiotic division. In contrast, the role of the maintenance DNA methylation pathway for regulation of meiotic prophase, or meiotic division, in the adult is not well understood. Here, by using conditional mutants for Np95 (nuclear protein 95 kDa, also known as Uhrf1) or Dnmt1 [DNA (cytosine-5)-methyltransferase 1], two proteins that are essential for maintenance DNA methylation, we reveal that both NP95 and DNMT1 are co-expressed in spermatogonia and that these factors are necessary for meiosis in male germ cells. We found that Np95- or Dnmt1-deficient spermatocytes exhibited spermatogenic defects involving synaptic failure during meiotic prophase. In addition, assembly of pericentric heterochromatin clusters in early meiotic prophase, a phenomenon that is required for subsequent pairing of homologous chromosomes, is disrupted in Np95-deficient as well as Dnmt1-deficient spermatocytes. Based on these observations, we propose that DNA methylation established in pre-meiotic spermatogonia regulates synapsis of homologous chromosomes, and in turn quality control of male germ cells. Maintenance DNA methylation, therefore, plays a role to ensure faithful transmission of both genetic and epigenetic information to offspring.
Project description:During spermatogenesis, mammalian spermatogonia undergo mitotic division, to maintain stem cell pool via self-renewal and generate differentiating progenitor cells for entry into meiotic prophase. During the perinatal stage, de novo DNA methylation occurring in pro-spermatogonia plays a key role to complete meiotic prophase and initiate meiotic division. In contrast, the role of the maintenance DNA methylation pathway for regulation of meiotic prophase, or meiotic division, in the adult is not well understood. Here, by using conditional mutants for Np95 (nuclear protein 95 kDa, also known as Uhrf1) or Dnmt1 [DNA (cytosine-5)-methyltransferase 1], two proteins that are essential for maintenance DNA methylation, we reveal that both NP95 and DNMT1 are co-expressed in spermatogonia and that these factors are necessary for meiosis in male germ cells. We found that Np95- or Dnmt1-deficient spermatocytes exhibited spermatogenic defects involving synaptic failure during meiotic prophase. In addition, assembly of pericentric heterochromatin clusters in early meiotic prophase, a phenomenon that is required for subsequent pairing of homologous chromosomes, is disrupted in Np95-deficient as well as Dnmt1-deficient spermatocytes. Based on these observations, we propose that DNA methylation established in pre-meiotic spermatogonia regulates synapsis of homologous chromosomes, and in turn quality control of male germ cells. Maintenance DNA methylation, therefore, plays a role to ensure faithful transmission of both genetic and epigenetic information to offspring.
Project description:The innate immune response is the first line of defense against pathogens, and factors that control this cellular response represent targets for treating both infectious and inflammatory diseases. Here, we reveal a novel role for the human helicase SETX, also previously implicated in amyotrophic lateral sclerosis (ALS4) and ataxia with oculomotor apraxia (AOA2), in controlling the magnitude of the antiviral response. Cells depleted for SETX and AOA2 patient-derived SETX-null cells show increased expression of antiviral mediators in response to infection. Mechanistically, this effect is achieved through SETX-mediated inhibition of RNAPII transcription of antiviral genes, and depends on SETX helicase activity. Our results suggest that SETX helps maintain the delicate balance between controlling viral infection and avoiding the potentially detrimental effects of an excessive antiviral response. More broadly, the observation that SETX can regulate the transcriptional activity of specific genes may have important implications for disorders where SETX function is compromised. A549 cells that were transfected with either control non-targeting or SETX-specific siRNAs were infected with the Influenza A virus (A/PR/8/34(ΔNS1) strain) at a multiplicity of infection (MOI) of 3 for 4 hours. Nuclei were then extracted and used to prepare Global Run-On Sequencing (GRO-seq) libraries.