Project description:The oocytes of most animals arrest at diplotene or diakinesis, but resume meiosis (meiotic maturation) in response to hormones. In C. elegans, maturation of the –1 oocyte requires the presence of sperm, Gas-adenylate cyclase-PKA signaling in the gonadal sheath cells, and germline function of two Tis11-like CCCH zinc-finger proteins, OMA-1 and OMA-2 (OMA proteins). Prior studies indicate that the OMA proteins redundantly repress the translation of specific mRNAs in oocytes (zif-1, mom-2, nos-2, glp-1) and early embryos (mei-1). We purified OMA-1-containing ribonucleoprotein particles (RNPs) and identified mRNAs that associate with OMA-1 in oocytes using microarrays. We examined the relative abundances of mRNAs in OMA-1 RNPs using high-throughput RNA sequencing. Previously identified targets of OMA-dependent translational repression in oocytes were found to be both enriched (>2-fold relative to input RNA) and abundant in purified OMA-1 RNPs. Furthermore, we verified that some of the newly identified mRNAs that share these characteristics are translationally repressed by OMA-1/2 in oocytes through sequences in their 3’UTRs. Although meiotic maturation is stimulated by sperm, we found that the mRNAs copurifying with OMA-1 are not significantly different in the presence and absence of sperm, suggesting that sperm-dependent signaling does not modify the suite of mRNAs stably associated with OMA-1. Further, several tested OMA-1-associated mRNAs were shown to be translationally repressed in both the presence and absence of sperm. C. elegans mRNAs that co-purify with OMA-1 were identified by deep-sequencing using the Illumina HiSeq 2000
Project description:The oocytes of most animals arrest at diplotene or diakinesis, but resume meiosis (meiotic maturation) in response to hormones. In C. elegans, maturation of the –1 oocyte requires the presence of sperm, Gas-adenylate cyclase-PKA signaling in the gonadal sheath cells, and germline function of two Tis11-like CCCH zinc-finger proteins, OMA-1 and OMA-2 (OMA proteins). Prior studies indicate that the OMA proteins redundantly repress the translation of specific mRNAs in oocytes (zif-1, mom-2, nos-2, glp-1) and early embryos (mei-1). We purified OMA-1-containing ribonucleoprotein particles (RNPs) and identified mRNAs that associate with OMA-1 in oocytes using microarrays. We examined the relative abundances of mRNAs in OMA-1 RNPs using high-throughput RNA sequencing. Previously identified targets of OMA-dependent translational repression in oocytes were found to be both enriched (>2-fold relative to input RNA) and abundant in purified OMA-1 RNPs. Furthermore, we verified that some of the newly identified mRNAs that share these characteristics are translationally repressed by OMA-1/2 in oocytes through sequences in their 3’UTRs. Although meiotic maturation is stimulated by sperm, we found that the mRNAs copurifying with OMA-1 are not significantly different in the presence and absence of sperm, suggesting that sperm-dependent signaling does not modify the suite of mRNAs stably associated with OMA-1. Further, several tested OMA-1-associated mRNAs were shown to be translationally repressed in both the presence and absence of sperm. RNA co-purifiying with OMA-1 (IP RNA) was isolated and compared to total lysate RNA (input RNA). Immunopurifications were performed, in triplicate, from lysates made from two different sterile strains. Sterile fog-1 adults lack sperm. Sterile spe-9 adults contain fertilization-incompetent sperm that promote meiotic maturation.
Project description:The oocytes of most animals arrest at diplotene or diakinesis, but resume meiosis (meiotic maturation) in response to hormones. In C. elegans, maturation of the –1 oocyte requires the presence of sperm, Gas-adenylate cyclase-PKA signaling in the gonadal sheath cells, and germline function of two Tis11-like CCCH zinc-finger proteins, OMA-1 and OMA-2 (OMA proteins). Prior studies indicate that the OMA proteins redundantly repress the translation of specific mRNAs in oocytes (zif-1, mom-2, nos-2, glp-1) and early embryos (mei-1). We purified OMA-1-containing ribonucleoprotein particles (RNPs) and identified mRNAs that associate with OMA-1 in oocytes using microarrays. We examined the relative abundances of mRNAs in OMA-1 RNPs using high-throughput RNA sequencing. Previously identified targets of OMA-dependent translational repression in oocytes were found to be both enriched (>2-fold relative to input RNA) and abundant in purified OMA-1 RNPs. Furthermore, we verified that some of the newly identified mRNAs that share these characteristics are translationally repressed by OMA-1/2 in oocytes through sequences in their 3’UTRs. Although meiotic maturation is stimulated by sperm, we found that the mRNAs copurifying with OMA-1 are not significantly different in the presence and absence of sperm, suggesting that sperm-dependent signaling does not modify the suite of mRNAs stably associated with OMA-1. Further, several tested OMA-1-associated mRNAs were shown to be translationally repressed in both the presence and absence of sperm.
Project description:The oocytes of most animals arrest at diplotene or diakinesis, but resume meiosis (meiotic maturation) in response to hormones. In C. elegans, maturation of the –1 oocyte requires the presence of sperm, Gas-adenylate cyclase-PKA signaling in the gonadal sheath cells, and germline function of two Tis11-like CCCH zinc-finger proteins, OMA-1 and OMA-2 (OMA proteins). Prior studies indicate that the OMA proteins redundantly repress the translation of specific mRNAs in oocytes (zif-1, mom-2, nos-2, glp-1) and early embryos (mei-1). We purified OMA-1-containing ribonucleoprotein particles (RNPs) and identified mRNAs that associate with OMA-1 in oocytes using microarrays. We examined the relative abundances of mRNAs in OMA-1 RNPs using high-throughput RNA sequencing. Previously identified targets of OMA-dependent translational repression in oocytes were found to be both enriched (>2-fold relative to input RNA) and abundant in purified OMA-1 RNPs. Furthermore, we verified that some of the newly identified mRNAs that share these characteristics are translationally repressed by OMA-1/2 in oocytes through sequences in their 3’UTRs. Although meiotic maturation is stimulated by sperm, we found that the mRNAs copurifying with OMA-1 are not significantly different in the presence and absence of sperm, suggesting that sperm-dependent signaling does not modify the suite of mRNAs stably associated with OMA-1. Further, several tested OMA-1-associated mRNAs were shown to be translationally repressed in both the presence and absence of sperm.
Project description:The PUF family of RNA binding proteins has a conserved role in maintaining stem cell self-renewal. FBF is a C. elegans PUF that is required to maintain germline stem cells (GSCs). To understand how FBF controls GSCs, we sought to identify is target mRNAs. Briefly, we immunoprecipitated FBF-mRNA complexes from worm extracts and then used microarrays to identify the FBF-associated mRNAs. To focus on germline targets of FBF, we used a FBF-GFP transgene under the control of a germline promoter and we used an anti-GFP antibody to purify FBF-GFP from worm extracts. In parallel, we also processed a strain expressing TUBULIN-GFP in the germline to control for mRNAs that non-specifically co-purify with GFP. We found that FBF associates with >1,000 unique mRNAs and likely controls a broad network of key cellular and developmental regulators. Experiment Overall Design: Worm extracts were prepared from synchronized adult C. elegans (24 h after L4 stage) expressing either a rescuing FBF-1-GFP or TUB-GFP transgene under the control of a germline promoter (pie-1). An immoblized anti-GFP antibody was then used to purify the GFP fusion proteins from extracts. RNA was then extracted from the pellets and analyzed on Affymetrix microarrays. Four biological replicates were performed, each consisting of a FBF-GFP and a TUB-GFP sample processed in parallel.
Project description:The PUF family of RNA binding proteins has a conserved role in maintaining stem cell self-renewal. FBF is a C. elegans PUF that is required to maintain germline stem cells (GSCs). To understand how FBF controls GSCs, we sought to identify is target mRNAs. Briefly, we immunoprecipitated FBF-mRNA complexes from worm extracts and then used microarrays to identify the FBF-associated mRNAs. To focus on germline targets of FBF, we used a FBF-GFP transgene under the control of a germline promoter and we used an anti-GFP antibody to purify FBF-GFP from worm extracts. In parallel, we also processed a strain expressing TUBULIN-GFP in the germline to control for mRNAs that non-specifically co-purify with GFP. We found that FBF associates with >1,000 unique mRNAs and likely controls a broad network of key cellular and developmental regulators.
Project description:To explore how ZSP-1 (and therefore Z granules) might contribute to germline RNAi, we asked if zsp-1(-) animals were able to produce 22G siRNAs in response to dsRNA exposure. We exposed wild-type and zsp-1(-) animals to dsRNA targeting the germline-expressed gene oma-1 and sequenced the resultant oma-1 22G siRNAs. We identified similar numbers of oma-1 siRNAs anti-sense to oma-1 after oma-1 RNAi on wild-type or zsp-1(-) animals. We also used this dataset to identify genes with differential level of targeted 22G siRNAs level in zsp-1(-) versus WT animals.
Project description:During oocyte maturation and the oocyte-to-embryo transition, key developmental regulators such as RNA-binding proteins coordinate translation of particular mRNAs and related developmental processes by binding to their cognate maternal mRNAs. In the nematode C. elegans, these processes are regulated by a set of CCCH zinc finger proteins. OMA-1 and OMA-2 are two functionally redundant CCCH zinc finger proteins that turnover rapidly during the first embryonic cell division. These turnovers are required for proper transition from oogenesis to embryogenesis. A gain-of-function mutant of OMA-1, oma-1(zu405), stabilizes and delays degradation of OMA-1, resulting in delayed turnover and mis-segregation of other cell fate determinants, which eventually causes embryonic lethality. We performed a large-scale forward genetic screen to identify suppressors of the oma-1(zu405) mutant. We show here that multiple alleles affecting functions of various APC/C subunits, including MAT-1, MAT-2, MAT-3, EMB-30, and FZY-1, suppress the gain-of-function mutant of OMA-1. Mutations in APC/C genes prevent OMA-1 enrichment in P granules and correct delayed degradation of downstream cell fate determinants including PIE-1, POS-1, MEX-3, and MEG-1. Transcriptome analysis also suggested that overall transcription in early embryos occurred after introducing mutations in APC/C genes into the oma-1(zu405) mutant. We demonstrated that only the activator FZY-1, but not FZR-1, is incorporated in the APC/C complex to regulate the oocyte-to-embryo transition. Our findings suggested a genetic relationship linking the APC/C complex and OMA-1, and support a model in which the APC/C complex promotes P granule accumulation and modifies RNA binding of OMA-1 to regulate the oocyte-to-embryo transition process.