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 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.
Project description:This phase I clinical trial tests the immune effects of fermented wheat germ in patients with advanced solid tumor cancers who are being treated with standard of care checkpoint inhibitors. Fermented wheat germ is a nutritional supplement that some claim is a "dietary food for special medical purposes for cancer patients" to support them in treatment. There have also been claims that fermented wheat germ is "clinically proven" and "recognized by medical experts" to "enhance oncological treatment" and boost immune response to cancer; however, there are currently no documented therapeutic effects of fermented wheat germ as a nutritional supplement. Checkpoint inhibitors, given as part of standard of care for advanced solid tumors, are a type of immunotherapy that may help the body’s immune system attack the cancer and may interfere with the ability of tumor cells to grow and spread. The information gained from this trial may allow researchers to determine if there is any value of giving fermented wheat germ with standard of care checkpoint inhibitors for patients with advanced solid tumor malignancies.
Project description:Germ plasm, the Balbiani body and nuage are evolutionary conserved structures essential for germ cell specification and maintenance. We describe Tdrd6a as a component of these structures with two distinct molecular functions. First, Tdrd6a facilitates the accumulation of the typical antisense-bias of piRNAs, without having effects on piRNA biogenesis signatures. Second, we show that Tdrd6a is required for Balbiani body and germ plasm integrity, and associates with RNA-binding proteins and germ plasm mRNAs. On the cell-biological level, maternally contributed Tdrd6a strongly impacts germ cell formation, but is dispensable for fertility. Using single-cell RNA-sequencing we demonstrate that Tdrd6a promotes early germ cell development and regulates the stoichiometry of germ plasm mRNAs. We propose that Tdrd6a functions as a scaffold to recruit correct ratios of germ plasm transcripts and to accumulate antisense piRNA complexes in order to ensure both specification and maintenance of germ cells.
Project description:Transposable elements (TEs) occupy large fraction of metazoan genomes and pose constant threat to genomic integrity. This threat is particularly critical in germ cells, as changes in the genome that are induced by TEs will be transmitted to the next generation. Small non-coding piwi interacting (pi)RNAs recognize and silence a diverse set of TEs in germ cells. In mice, piRNA-guided transposon repression correlates with establishment of CpG DNA methylation on their sequences, yet the mechanism and the spectrum of genomic targets of piRNA silencing are unknown. Here we show that in addition to DNA methylation, the piRNA pathway is required to maintain a high level of the repressive H3K9me3 histone modification on long interspersed nuclear elements (LINEs) in germ cells. piRNA-dependent chromatin repression targets exclusively full-length elements of actively transposing LINE families, demonstrating the remarkable ability of the piRNA pathway to recognize active elements among the large number of genomic transposon fragments. Total of 34 libraries were analyzed. In case of ChIP libraries, every 'input' sample was used for normalization of the respective ChIP (H3K9me3 or H3) sample; the input libraries preceed ChIP libraries in the list below. There are four replicates (input-ChIP pairs) for H3K9me3 ChIP on liver cells, two for ChIP on testicular somatic cells for each genotype (Miwi2 Het and KO); and four for ChIP on male germ cells for each genotype (one from FACS-sorted germ cells, and three from MACS-sorted germ cells). Each replicate has a Het/KO pair, and the respective libraries were cloned from the material isolated from littermates. One H3 ChIP for each genotype is included, with respective inputs.