Similar Datasets
Project description:In C. elegans, the H3K4me2 demethylase, SPR-5, and the H3K9 methyltransferase, MET-2, are maternally deposited into the oocyte where they reprogram histone methylation to prevent somatic expression of germline genes. Here, we show that the progeny of spr-5; met-2 mutants display a severe developmental delay that is associated with the ectopic expression of germline genes targeted by the H3K36me2/3 methyltransferase, MES-4. Maternally deposited MES-4 maintains H3K36me2/3 at a subset of germline genes (hereafter referred to as MES-4 germline genes) in a transcription-independent manner, and this is required for germline proliferation in the subsequent generation. By performing ChIP-seq on L1 progeny from spr-5; met-2 mutants, we find that MES-4 germline genes ectopically accumulate H3K36me3 in somatic tissues. Additionally, knocking down MES-4 suppresses the ectopic expression of MES-4 germline genes and rescues the developmental delay. These data suggest a model where SPR-5, MET-2 and MES-4 carefully balance the inheritance of histone methylation from the parental germline to ensure the proper specification of germline versus soma in the progeny. Without SPR-5; MET-2 maternal reprogramming, somatic cells struggle to specify their proper cell fate amongst the background noise of inappropriate germline gene transcription, leading to a severe developmental delay.
2020-01-17 | GSE143838 | GEO
Project description:In C. elegans, the H3K4me2 demethylase, SPR-5, and the H3K9 methyltransferase, MET-2, are maternally deposited into the oocyte where they reprogram histone methylation to prevent somatic expression of germline genes. Here, we show that the progeny of spr-5; met-2 mutants display a severe developmental delay that is associated with the ectopic expression of germline genes targeted by the H3K36me2/3 methyltransferase, MES-4. Maternally deposited MES-4 maintains H3K36me2/3 at a subset of germline genes (hereafter referred to as MES-4 germline genes) in a transcription-independent manner, and this is required for germline proliferation in the subsequent generation. By performing ChIP-seq on L1 progeny from spr-5; met-2 mutants, we find that MES-4 germline genes ectopically accumulate H3K36me3 in somatic tissues. Additionally, knocking down MES-4 suppresses the ectopic expression of MES-4 germline genes and rescues the developmental delay. These data suggest a model where SPR-5, MET-2 and MES-4 carefully balance the inheritance of histone methylation from the parental germline to ensure the proper specification of germline versus soma in the progeny. Without SPR-5; MET-2 maternal reprogramming, somatic cells struggle to specify their proper cell fate amongst the background noise of inappropriate germline gene transcription, leading to a severe developmental delay.
2020-01-17 | GSE143837 | GEO
Project description:C. elegans establishes germline versus soma by balancing inherited histone methylation
| PRJNA601800 | ENA
Project description:C. elegans establishes germline versus soma by balancing inherited histone methylation [ChIP-seq]
| PRJNA601803 | ENA
Project description:C. elegans establishes germline versus soma by balancing inherited histone methylation [RNA-seq]
| PRJNA601804 | ENA
Project description:Unlike the soma, which ages during the lifespan of multicellular organisms, the germ line traces an essentially immortal lineage. Genomic instability in somatic cells increases with age, and this decline in somatic maintenance might be regulated to facilitate resource reallocation towards reproduction at the expense of cellular senescence. Here we show that Caenorhabditis elegans mutants with increased longevity exhibit a soma-to-germline transformation of gene expression programs normally limited to the germ line. Decreased insulin-like signalling causes the somatic misexpression of the germline-limited pie-1 and pgl family of genes in intestinal and ectodermal tissues. The forkhead boxO1A (FOXO) transcription factor DAF-16, the major transcriptional effector of insulin-like signalling, regulates pie-1 expression by directly binding to the pie-1 promoter. The somatic tissues of insulin-like mutants are more germline-like and protected from genotoxic stress. Gene inactivation of components of the cytosolic chaperonin complex that induce increased longevity also causes somatic misexpression of PGL-1. These results indicate that the acquisition of germline characteristics by the somatic cells of C. elegans mutants with increased longevity contributes to their increased health and survival.
| S-EPMC2716045 | biostudies-literature
Project description:Methylated cytosines deaminate at higher rates than unmethylated cytosines, and the lesions they produce are repaired less efficiently. As a result, methylated cytosines are mutational hotspots. Here, combining rare polymorphism and base-resolution methylation data in humans, Arabidopsis thaliana, and rice (Oryza sativa), we present evidence that methylation state affects mutation dynamics not only at the focal cytosine but also at neighboring nucleotides. In humans, contrary to prior suggestions, we find that nucleotides in the close vicinity (±3 bp) of methylated cytosines mutate less frequently. Reduced mutability around methylated CpGs is also observed in cancer genomes, considering single nucleotide variants alongside tissue-of-origin-matched methylation data. In contrast, methylation is associated with increased neighborhood mutation risk in A. thaliana and rice. The difference in neighborhood mutation risk is less pronounced further away from the focal CpG and modulated by regional GC content. Our results are consistent with a model where altered risk at neighboring bases is linked to lesion formation at the focal CpG and subsequent long-patch repair. Our findings indicate that cytosine methylation has a broader mutational footprint than is commonly assumed.
| S-EPMC7153944 | biostudies-literature
Project description:Multicellular organisms coordinate tissue specific responses to environmental information via both cell-autonomous and non-autonomous mechanisms. In addition to secreted ligands, recent reports implicated release of small RNAs in regulating gene expression across tissue boundaries. Here, we show that the conserved poly-U specific endoribonuclease ENDU-2 in C. elegans is secreted from the soma and taken-up by the germline to ensure germline immortality at elevated temperature. ENDU-2 binds to mature mRNAs and negatively regulates mRNA abundance both in the soma and the germline. While ENDU-2 promotes RNA decay in the soma directly via its endoribonuclease activity, ENDU-2 prevents misexpression of soma-specific genes in the germline and preserves germline immortality independent of its RNA-cleavage activity. In summary, our results suggest that the secreted RNase ENDU-2 regulates gene expression across tissue boundaries in response to temperature alterations and contributes to maintenance of stem cell immortality, probably via retaining a stem cell specific program of gene expression.
| S-EPMC7904951 | biostudies-literature
Project description:In all animals examined, somatic cells of the gonad control multiple biological processes essential for germline development. Gap junction channels, composed of connexins in vertebrates and innexins in invertebrates, permit direct intercellular communication between cells and frequently form between somatic gonadal cells and germ cells. Gap junctions comprise hexameric hemichannels in apposing cells that dock to form channels for the exchange of small molecules. Here we report essential roles for two classes of gap junction channels, composed of five innexin proteins, in supporting the proliferation of germline stem cells and gametogenesis in the nematode Caenorhabditis elegans. Transmission electron microscopy of freeze-fracture replicas and fluorescence microscopy show that gap junctions between somatic cells and germ cells are more extensive than previously appreciated and are found throughout the gonad. One class of gap junctions, composed of INX-8 and INX-9 in the soma and INX-14 and INX-21 in the germ line, is required for the proliferation and differentiation of germline stem cells. Genetic epistasis experiments establish a role for these gap junction channels in germline proliferation independent of the glp-1/Notch pathway. A second class of gap junctions, composed of somatic INX-8 and INX-9 and germline INX-14 and INX-22, is required for the negative regulation of oocyte meiotic maturation. Rescue of gap junction channel formation in the stem cell niche rescues germline proliferation and uncovers a later channel requirement for embryonic viability. This analysis reveals gap junctions as a central organizing feature of many soma-germline interactions in C. elegans.
| S-EPMC4224157 | biostudies-literature
Project description:Gametogenesis is dependent on the expression of germline-specific genes. However, it remains unknown how the germline epigenome is distinctly established from that of somatic lineages. Here we show that genes commonly expressed in somatic lineages and spermatogenesis-progenitor cells undergo repression in a genome-wide manner in late stages of the male germline and identify underlying mechanisms. SCML2, a germline-specific subunit of a Polycomb repressive complex 1 (PRC1), establishes the unique epigenome of the male germline through two distinct antithetical mechanisms. SCML2 works with PRC1 and promotes RNF2-dependent ubiquitination of H2A, thereby marking somatic/progenitor genes on autosomes for repression. Paradoxically, SCML2 also prevents RNF2-dependent ubiquitination of H2A on sex chromosomes during meiosis, thereby enabling unique epigenetic programming of sex chromosomes for male reproduction. Our results reveal divergent mechanisms involving a shared regulator by which the male germline epigenome is distinguished from that of the soma and progenitor cells.
| S-EPMC4391279 | biostudies-literature