Project description:FOG-1/CPEB and FOG-3/Tob are the terminal regulators of the sex determination in C. elegans germ cells. CPEB and Tob proteins are both translational regulators. To investigate how FOG-1 and FOG-3 regulate germ cell sex determination we sought to identify the target mRNAs. We used transgenic epitope tagged animals (3xMyc::FOG-1 and FOG-3::3xFLAG). To identify the mRNA targets of FOG-1/CPEB and FOG-3/Tob on a genome wide scale we used RNA immunoprecipitation followed by microarray analysis. We found 81 putative mRNA targets of FOG-1 and 722 putative targets of FOG-3. 76 target mRNAs were common to both FOG-1 and FOG-3. FOG-1 RNA-coimmunoprecipitation (RIP) samples were prepared as follows. Parallel RIPs were performed with wild type animals as the control IP. Worm extracts were made from wildtype and 3xMyc::FOG-1 late L3/early L4 animals. Myc affinity gel was used to immunoprecipitate 3xMyc::FOG-1 from the extracts. RNA was extracted from the pellets and analyzed on Affymetrix microarrays. 7 biological replicates of both 3xMyc::FOG-1 and wildtype were used. FOG-3 RNA-coimmunoprecipitation (RIP) samples were prepared as follows. Parallel RIPs were performed with wild type animals as the control IP. Worm extracts were made from wildtype and FOG-3::3xFLAG late L3/early L4 animals. Myc affinity gel was used to immunoprecipitate FOG-3::3xFLAG from the extracts. RNA was extracted from the pellets and analyzed on Affymetrix microarrays. 7 biological replicates of both FOG-3::3xFLAG and wildtype were used.
Project description:FOG-1/CPEB and FOG-3/Tob are the terminal regulators of the sex determination in C. elegans germ cells. CPEB and Tob proteins are both translational regulators. To investigate how FOG-1 and FOG-3 regulate germ cell sex determination we sought to identify the target mRNAs. We used transgenic epitope tagged animals (3xMyc::FOG-1 and FOG-3::3xFLAG). To identify the mRNA targets of FOG-1/CPEB and FOG-3/Tob on a genome wide scale we used RNA immunoprecipitation followed by microarray analysis. We found 81 putative mRNA targets of FOG-1 and 722 putative targets of FOG-3. 76 target mRNAs were common to both FOG-1 and FOG-3.
Project description:In this experiment, steady-state mRNA levels were determined for replicated samples of N2 (wild-type reference) and fog-2(q71) homozygous mutant C. elegans. All samples were adult XX animals, which for N2 are self-fertile hermaphrodites and for fog-2(q71) spermless hermaphrodites, i.e. true females. For the fog-2 mutant animals, only those that had mated with males, and were thus gravid, were picked for RNA isolation. This ensures that all comparisons are between similar, embryo-containing animals. The experiment was motivated by the role of FOG-2 in post-transcriptional control of gene expression in germ cells, inferred from its the germline-specific phenotype of its loss and from its physical associated with the GLD-1 RNA-binding protein. Specifically, a possible role for FOG-2 in influencing mRNA stability was addressed.
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:One of the most abundant RNA modifications is N6-methyladenosine (m6A). RNA from all forms of life, including viruses, contain m6A. This modification has been detected in many types of RNAs, such as mRNA, ribosomal RNA, long non-coding RNAs, small nuclear RNAs and microRNAs. Diverse set of proteins have been characterized to methylate, demethylate and specifically bind to this modification in different organisms. C. elegans is a unique model organism with abundant m6A modification, although its genome does not code for orthologs of the well characterized m6A methyltransferase METTL3/METTL14 complex or the demethylases FTO or ALKBH5. Furthermore, orthologs of the YTH family m6A reader proteins seem to be absent from the worm genome as well. To gain insights into how this modification is installed in this organism, we set out to identify enzymes that contribute to the abundant level of m6A in C. elegans. We designed a targeted RNAi screen by which the expression of 22 candidate putative RNA methyltransferase genes are knocked down. We measured global RNA methylation level by HPLC-MS/MS analysis after two generations of RNAi-mediated knock down. The knock down of two candidate methyltransferases resulted in a decrease in global m6A level in total RNA. The first methyltransferase, F33A8.4, is an ortholog of the human ZCCHC4 gene. The second methyltransferase, C38D4.9, is an ortholog of the human METTL5 gene. In order to determine if ZCCHC4 or METTL5 are involved in the deposition of m6A at the mRNA level, m6A-RIP-seq experiments were performed in mRNA derived from WT (N2), ZCCHC4 KO, METTL5 KO and ZCCHC4/METTL5 dKO C. elegans embryos.