Project description:With the aim to determine the extent of germline feminization in feminized male worms, we performed differential gene expression profiling of isolated gonads and whole worms between fog-1(q253) XO males and XX females.
Project description:Paternal contributions to epigenetic inheritance are not well understood. We report that in C. elegans sperm, the genome is packaged in nucleosomes and carries a histone-based epigenetic memory of gene expressions during spermatogenesis. In mature sperm, genes with spermatogenesis-specific expression are marked with both active and represseive histone modifications and genes with oogenesis-enriched expression are marked with active histone modifications. We showed that genes with oogenesis-enriched expression are in fact transcribed in spermatogenic germlines. We tested if sperm chromatin marking is necessary for germ cell development in offspring that inherit both sperm and oocyte chromosomes, using male parents that either can or cannot generate H3K27me3. Males homozygous for a mutation in mes-3, which encodes a member of the worm PRC2 complex, were mated with feminized mes-3/+ heterozygous worms to produce offspring that inherited sperm chromosomes lacking H3K27me3. We call these offspring M+P- or MpPm (Maternal chromosomes are + or plus for H3K27me3, Paternal chromosomes are - or minus for H3K27me3). Most of the resulting mes-3 homozygous M+P- offspring developed into sterile adults in this sensitized genetic background. In contrast, genetically identical control offspring that received appropriate H3K27me3-marked sperm chromosomes (M+P+ or MpPp) displayed low sterility. We compared genes mis-regulated in mes-3 male germlines versus control him-8 male germlines, mature sperm from those germlines, and germlines of mes-3 mutant F1 offspring that inherited sperm chromatin lacking H3K27me3 (M+P-) versus inherited sperm chromatin with H3K27me3 (M+P+), based on RNA-seq.
Project description:Histone H3 Lys 4 methylation (H3K4me) is deposited by the conserved SET1/MLL methyltransferases acting in multiprotein complexes including Ash2 and Wdr5. While individual subunits contribute to complex activity, how they influence gene expression in a specific tissue remains largely unknown. In caenorhabditis elegans, SET-2/SET1, WDR-5.1 and ASH-2 are differentially required for germline H3K4 methylation. Using expression profiling on germlines from animals lacking set-2, ash-2 or wdr-5.1, we show that these subunits play unique and redundant functions to promote expression of germline genes and repress somatic genes. We further show that in set-2 and wdr-5.1 deficient germlines, somatic gene misexpression is associated with conversion of germ cells into somatic cells, and that nuclear RNAi acts in parallel with SET-2 and WDR-5.1 to maintain germline identity. These findings uncover a unique role for SET-2 and WDR-5.1 in preserving germline pluripotency, and underline the complexity of the cellular network regulating this process. Gene misregulation in SET1/set-2, wdr-5.1 and ash-2 defective germlines
Project description:We compare whole-animal RNA-seq transcriptomes for C. elegans males and hermaphrodites from the late L3 larval stage to young adulthood. During this interval, male sexual structures develop, including extensive neurogenesis and synaptogenesis that nearly doubles the size of the nervous system. Previous genome-wide expression studies in C. elegans have usually focused on only one sex – the hermaphrodite, and there are a relatively large number of predicted genes that still remain without meaningful annotation. In the present study, differential expression analysis of the RNA-seq data revealed 1,751 genes expressed at a higher level in the male. By differential expression analysis, unbiased gene correlation analysis, and a guilt-by-association approach, we identified new transcription factors required for differentiation of male genital structures, semen proteins, and candidates for previously-unknown components for synapse function. The results validate the dataset as a rich resource for future gene discovery in C. elegans.
Project description:The nematode Caenorhabditis elegans contains each of the broad classes of eukaryotic small RNAs, including microRNAs (miRNAs), endogenous small-interfering RNAs (endo-siRNAs) and piwi-interacting RNAs (piRNAs). To better understand the evolution of these regulatory RNAs, we deep sequenced small RNAs from C. elegans and three closely related nematodes: C. briggsae, C. remanei and C. brenneri. The results reveal a fluid landscape of small RNA pathways with essentially no conservation of individual sequences aside from a subset of miRNAs. We identified 52 miRNA families that are conserved in each of the four species as well as numerous miRNAs that are species specific or shared between only two or three species. Despite a lack of conservation of individual piRNAs and siRNAs many of the features of each pathway, including genomic distribution, are conserved. We show that in each species, 26G siRNAs trigger stage-specific secondary siRNA formation. We also observe that piRNAs trigger siRNA formation from targets containing up to three mismatches in each species. Finally, we show that nematodes produce two distinct sex-specific classes of piRNAs, suggesting different roles for piRNAs in male and female germlines. Sequencing small RNAs from four Caenorhabditis species: C. elegans, C. briggsae, C. remanei and C. brenneri
Project description:We compare whole-animal RNA-seq transcriptomes for C. elegans males and hermaphrodites from the late L3 larval stage to young adulthood. During this interval, male sexual structures develop, including extensive neurogenesis and synaptogenesis that nearly doubles the size of the nervous system. Previous genome-wide expression studies in C. elegans have usually focused on only one sex â the hermaphrodite, and there are a relatively large number of predicted genes that still remain without meaningful annotation. In the present study, differential expression analysis of the RNA-seq data revealed 1,751 genes expressed at a higher level in the male. By differential expression analysis, unbiased gene correlation analysis, and a guilt-by-association approach, we identified new transcription factors required for differentiation of male genital structures, semen proteins, and candidates for previously-unknown components for synapse function. The results validate the dataset as a rich resource for future gene discovery in C. elegans. To analyze gene expression during sexual maturation in C. elegans, we performed RNA-seq for five samples for each sex ranging at 6 hr intervals from late L3 to young adult stages
Project description:Understanding genome and gene function in a whole organism requires us to fully comprehend the life cycle and the physiology of the organism in question. Caenorhabditis elegans XX animals are hermaphrodites that exhaust their sperm after 3 d of egg-laying. Even though C. elegans can live for many days after cessation of egg-laying, the molecular physiology of this state has not been as intensely studied as other parts of the life cycle, despite documented changes in behavior and metabolism. To study the effects of sperm depletion and aging of C. elegans during the first 6 d of adulthood, we measured the transcriptomes of first-day adult hermaphrodites and sixth-day sperm-depleted adults, and, at the same time points, mutant fog-2(lf) worms that have a feminized germline phenotype. We found that we could separate the effects of biological aging from sperm depletion. For a large subset of genes, young adult fog-2(lf) animals had the same gene expression changes as sperm-depleted sixth-day wild-type hermaphrodites, and these genes did not change expression when fog-2(lf) females reached the sixth day of adulthood. Taken together, this indicates that changing sperm status causes a change in the internal state of the worm, which we call the female-like state. Our data provide a high-quality picture of the changes that happen in global gene expression throughout the period of early aging in the worm.
Project description:Young adult N2 Caenorhabditis elegans were infected with Enterococcus faecalis or Enterococcus faecium for 8 h to determine the transcriptional host response to each enterococcal species. Analysis of differential gene expression in C. elegans young adults exposed to four different bacteria: heat-killed Escherichia coli strain OP50 (control), wild-type E. faecalis MMH594, wild-type E. faecium E007, or Bacillus subtilis PY79 (sigF::kan). Samples were analyzed at 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection. Brain-heart infusion agar plates (10 ug/ml kanamycin) were used.
Project description:Young adult fer-15;fem-1 Caenorhabditis elegans were infected with Staphylococcus aureus for 8 h to determine the transcriptional host response to Staphylococcus aureus. Analysis of differential gene expression in C. elegans young adults exposed to two different bacteria: E. coli strain OP50 (control), wild-type Staphylococcus aureus RN6390. Samples were analyzed at 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection. Keywords: response to pathogen infection, innate immunity, host-pathogen interactions