Caenorhabditis elegans
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PROVIDER: PRJNA281372 | ENA |
REPOSITORIES: ENA
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Project description:P granules in C. elegans are required for fertility and function to maintain germ cell identity and pluripotency. Sterility in the absence of P granules is often accompanied by the mis-expression of soma-specific proteins and the initiation of somatic differentiation in germ cells. To investigate whether this is caused by the accumulation of somatic transcripts, we performed mRNA-seq on dissected germlines with and without P granules. Strikingly, we found that somatic transcripts do not increase in the young adult germline when P granules are impaired. Instead, we found that impairing P granules causes sperm-specific mRNAs to become highly overexpressed. This includes the accumulation of major sperm protein (MSP) transcripts in germ cells, a phenotype that is suppressed by feminization of the germline. A core component of P granules, the endo-siRNA-binding Argonaute protein CSR-1, has recently been ascribed with the ability to license transcripts for germline expression. However, impairing CSR-1 has very little effect on the accumulation of its mRNA targets. Instead, we found that CSR-1 functions with P granules to prevent MSP and sperm-specific mRNAs from being transcribed in the hermaphrodite germline. These findings suggest that P granules protect germline integrity through two different mechanisms, by 1) preventing the inappropriate expression of somatic proteins at the level of translational regulation, and by 2) functioning with CSR-1 to limit the domain of sperm-specific expression at the level of transcription. Four biological replicates of each condition (empty vector control, P granule RNAi, and CSR-1 RNAi germlines) were collected for total RNA.
2015-05-20 | E-GEOD-67954 | biostudies-arrayexpress
Project description:P granules in C. elegans are required for fertility and function to maintain germ cell identity and pluripotency. Sterility in the absence of P granules is often accompanied by the mis-expression of soma-specific proteins and the initiation of somatic differentiation in germ cells. To investigate whether this is caused by the accumulation of somatic transcripts, we performed mRNA-seq on dissected germlines with and without P granules. Strikingly, we found that somatic transcripts do not increase in the young adult germline when P granules are impaired. Instead, we found that impairing P granules causes sperm-specific mRNAs to become highly overexpressed. This includes the accumulation of major sperm protein (MSP) transcripts in germ cells, a phenotype that is suppressed by feminization of the germline. A core component of P granules, the endo-siRNA-binding Argonaute protein CSR-1, has recently been ascribed with the ability to license transcripts for germline expression. However, impairing CSR-1 has very little effect on the accumulation of its mRNA targets. Instead, we found that CSR-1 functions with P granules to prevent MSP and sperm-specific mRNAs from being transcribed in the hermaphrodite germline. These findings suggest that P granules protect germline integrity through two different mechanisms, by 1) preventing the inappropriate expression of somatic proteins at the level of translational regulation, and by 2) functioning with CSR-1 to limit the domain of sperm-specific expression at the level of transcription.
2015-05-20 | GSE67954 | GEO
Project description:Germ cells contain non-membrane bound cytoplasmic organelles that help maintain germline integrity. In C. elegans they are called P granules; without them, the germline undergoes partial masculinization or aberrant differentiation. One key P-granule component is the Argonaute CSR-1, a small-RNA binding protein that antagonizes accumulation of sperm-specific transcripts in developing oocytes. Loss of CSR-1 or components of its pathway results in a very specific, enlarged P-granule phenotype. In a forward screen to identify mutants with abnormal P granules, ten alleles were recovered with csr-1 P-granule phenotypes, eight of which contain mutations in known CSR-1 pathway components (csr-1, ego-1, ekl-1, and drh-3). The remaining two alleles are in a novel gene now called elli-1 (enlarged germline granules). ELLI-1 is first expressed in primordial germ cells during mid-embryogenesis and continues to be expressed in the adult germline. While ELLI-1 forms cytoplasmic aggregates, they occasionally dock, but do not co-localize with P granules. Instead, the majority of ELLI-1 aggregates accumulate in the shared germline cytoplasm. In elli-1 mutants, several genes that promote RNAi and P-granule accumulation are upregulated, and embryonic lethality, sterility, and RNAi resistance in a hypomorphic drh-3 allele is enhanced. Like mutations in other CSR-1 pathway components, elli-1 is an enhancer of glp-1 sterility, suggesting that ELLI-1 functions with the CSR-1 pathway to modulate RNAi activity, P-granule accumulation, and post-transcriptional expression in the germline.
2016-06-08 | GSE82322 | GEO
Project description:Through high-throuhgput RNA-sequencing, this study identifies mRNAs that are differentially expressed between plp-1(ok2155) and wild-type C. elegans. Analysed results are published in Development. 2020 Oct 13:dev.195578. doi: 10.1242/dev.195578. PMID: 33051256 Abstract of the publication: The germ line genome is guarded against invading foreign genetic elements by small RNA-dependent gene-silencing pathways. Components of these pathways localize to, or form distinct aggregates in the vicinity of, germ granules. These components and their dynamics in and out of granules are currently being intensively studied. Here, we report the identification of PLP-1, a C. elegans protein related to the human single-stranded nucleic acid-binding protein called Pur-alpha, as a component of germ granules in C. elegans We show that PLP-1 is essential for silencing different types of transgenes in the germ line, and for suppressing the expression of several endogenous genes controlled by the germline gene-silencing pathways. Our results reveal that PLP-1 functions downstream of small RNA biogenesis during initiation of gene silencing. Based on these results and the earlier findings that Pur-alpha proteins interact with both RNA and protein, we propose PLP-1 couples certain RNAs with their protein partners in the silencing complex. Its orthologs localized on RNA granules may similarly contribute to germline gene silencing in other organisms.
2020-11-07 | GSE161011 | GEO
Project description:The C. elegans CSR-1 argonaute pathway counteracts epigenetic silencing to promote germline gene expression
| PRJNA214176 | ENA
Project description:In the Caenorhabditis elegans germline, thousands of mRNAs are concomitantly expressed with antisense 22G-RNAs, which are loaded into the Argonaute CSR-1. Despite their essential functions for animal fertility and embryonic development, how CSR-1 22G-RNAs are produced remains unknown. Here, we show that CSR-1 slicer activity is primarily involved in triggering the synthesis of small RNAs on the coding sequences of germline mRNAs and post-transcriptionally regulates a fraction of targets. CSR-1-cleaved mRNAs prime the RNA-dependent RNA polymerase, EGO-1, to synthesize 22G-RNAs in phase with ribosome translation in the cytoplasm, in contrast to other 22G-RNAs mostly synthesized in germ granules. Moreover, codon optimality and efficient translation antagonize CSR-1 slicing and 22G-RNAs biogenesis. We propose that codon usage differences encoded into mRNA sequences might be a conserved strategy in eukaryotes to regulate small RNA biogenesis and Argonaute targeting
2021-04-23 | PXD020293 | Pride
Project description:The C. elegans genome encodes nineteen functional Argonaute proteins that utilize 22G-RNAs, 26G-RNAs, miRNAs, or piRNAs to regulate their target transcripts. Only one of these proteins is essential under normal laboratory conditions: CSR-1. While CSR-1 has been studied in various developmental and functional contexts, nearly all studies investigating CSR-1 have overlooked the fact that the csr-1 locus encodes two isoforms. These isoforms differ by an additional 163 amino acids present in the N-terminus of CSR-1a. Using CRISPR-Cas9 genome editing to introduce GFP::3xFLAG epitopes into the long (CSR-1a) and short (CSR-1b) isoforms of CSR-1, we identified differential expression patterns for the two isoforms. CSR-1a is expressed specifically during spermatogenesis and in select somatic tissues, including the intestine. In contrast, CSR-1b, is expressed constitutively in the germline. Essential functions of csr-1 described in the literature coincide with CSR-1b. In contrast,CSR-1a plays tissue specific functions during spermatogenesis, where it integrates into a spermatogenesis sRNA regulatory network including ALG-3, ALG-4, and WAGO-10 that is necessary for male fertility. CSR-1a is also required in the intestine for the silencing of repetitive transgenes. Sequencing of small RNAs associated with each CSR-1 isoform reveals that CSR-1a engages with 22G- and 26G-RNAs, while CSR-1b interacts with only 22G-RNAs to regulate distinct groups of germline genes and regulate both sperm and oocyte-mediated fertility.
2020-07-19 | GSE154678 | GEO
Project description:The mechanisms of RNA-binding proteins (RBPs)-mediated post-transcriptional regulation of pre-existing mRNAs, which is essential for spermatogenesis, remains poorly understood. Here, we identify a germline-specific mitochondrial RBP AMG-1, a homolog of mammalian LRPPRC, required for spermatogenesis in C. elegans. amg-1 mutation hinders germline development without affecting somatic development and leads to the aberrant mitochondrial morphology and structure associated with mitochondrial dysfunctions specifically in germline. We demonstrate that AMG-1 is most frequently bound to mtDNA-encoded 12S and 16S ribosomal RNA, the essential components of mitochondrial ribosome, and that 12S rRNA expression mediated by AMG-1 is crucial for germline mitochondrial protein homeostasis. Besides, mitochondrial dysfunction by AMG-1 mutation triggers sperm apoptosis in C. elegans. Furthermore, SLRP-1, the homolog of mammalian SLIRP in C. elegans, interacts with AMG-1 genetically to regulate germline development and reproductive success in C. elegans. Taken together, these findings reveal the novel function of mtRBP in specifically regulating germline development.
2023-01-16 | GSE222138 | GEO
Project description:The mechanisms of RNA-binding proteins (RBPs)-mediated post-transcriptional regulation of pre-existing mRNAs, which is essential for spermatogenesis, remains poorly understood. Here, we identify a germline-specific mitochondrial RBP AMG-1, a homolog of mammalian LRPPRC, required for spermatogenesis in C. elegans. amg-1 mutation hinders germline development without affecting somatic development and leads to the aberrant mitochondrial morphology and structure associated with mitochondrial dysfunctions specifically in germline. We demonstrate that AMG-1 is most frequently bound to mtDNA-encoded 12S and 16S ribosomal RNA, the essential components of mitochondrial ribosome, and that 12S rRNA expression mediated by AMG-1 is crucial for germline mitochondrial protein homeostasis. Besides, mitochondrial dysfunction by AMG-1 mutation triggers sperm apoptosis in C. elegans. Furthermore, SLRP-1, the homolog of mammalian SLIRP in C. elegans, interacts with AMG-1 genetically to regulate germline development and reproductive success in C. elegans. Taken together, these findings reveal the novel function of mtRBP in specifically regulating germline development.
2023-01-16 | GSE222137 | GEO
Project description:CSR-1 is an essential Argonaute protein that binds to a subclass of 22G-RNAs targeting most germline-expressed genes. Here we show that the two isoforms of CSR-1 have distinct expression patterns; CSR-1B is ubiquitously expressed throughout the germline and during all stages of development while CSR-1A expression is restricted to germ cells undergoing spermatogenesis. Furthermore, CSR-1A associates preferentially with 22G-RNAs mapping to spermatogenesis-specific genes whereas CSR-1B-bound small RNAs map predominantly to oogenesis-specific genes. Interestingly, the exon unique to CSR-1A contains multiple dimethylarginine modifications, which are necessary for the preferential binding of CSR-1A to spermatogenesis-specific 22G-RNAs. Thus, we have discovered a regulatory mechanism for C. elegans Argonaute proteins that allows for specificity of small RNA binding between similar Argonaute proteins with overlapping temporal and spatial localization.
2021-06-17 | PXD021227 | Pride