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:An extended meiotic prophase is a hallmark of oogenesis. Hormonal signaling activates the CDK1/cyclin B kinase to promote oocyte meiotic maturation, which involves nuclear and cytoplasmic events. Nuclear maturation encompasses nuclear envelope breakdown, meiotic spindle assembly, and chromosome segregation. Cytoplasmic maturation involves major changes in oocyte protein translation and cytoplasmic organelles and is poorly understood. In the nematode Caenorhabditis elegans, sperm release the major sperm protein (MSP) hormone to promote oocyte growth and meiotic maturation. Large translational regulatory ribonucleoprotein (RNP) complexes containing the RNA-binding proteins OMA-1, OMA-2, and LIN-41 regulate meiotic maturation downstream of MSP signaling. To understand the control of translation during meiotic maturation, we purified LIN-41-containing RNPs and characterized their protein and RNA components. Protein constituents of LIN-41 RNPs include essential RNA-binding proteins, the GLD-2 cytoplasmic poly(A) polymerase, the CCR4-NOT deadenylase complex, and translation initiation factors. RNA sequencing defined mRNAs associated with both LIN-41 and OMA-1, as well as sets of mRNAs associated with either LIN-41 or OMA-1. Genetic and genomic evidence suggests that GLD-2, which is a component of LIN-41 RNPs, stimulates the efficient translation of many LIN-41-associated transcripts. We analyzed the translational regulation of two transcripts specifically associated with LIN-41 that encode the RNA regulators SPN-4 and MEG-1. We found that LIN-41 represses translation of spn-4 and meg-1, whereas OMA-1 and OMA-2 promote their expression. Upon their synthesis, SPN-4 and MEG-1 assemble into LIN-41 RNPs prior to their functions in the embryo. This study defines a translational repression-to-activation switch as a key element of cytoplasmic maturation.
Project description:An extended meiotic prophase is a hallmark of oogenesis. Hormonal signaling activates the CDK1/cyclin B kinase to promote oocyte meiotic maturation, which involves nuclear and cytoplasmic events. Nuclear maturation encompasses nuclear envelope breakdown, meiotic spindle assembly, and chromosome segregation. Cytoplasmic maturation involves major changes in oocyte protein translation and cytoplasmic organelles and is poorly understood. In the nematode Caenorhabditis elegans, sperm release the major sperm protein (MSP) hormone to promote oocyte growth and meiotic maturation. Large translational regulatory ribonucleoprotein (RNP) complexes containing the RNA-binding proteins OMA-1, OMA-2, and LIN-41 regulate meiotic maturation downstream of MSP signaling. To understand the control of translation during meiotic maturation, we purified LIN-41-containing RNPs and characterized their protein and RNA components. Protein constituents of LIN-41 RNPs include essential RNA-binding proteins, the GLD-2 cytoplasmic poly(A) polymerase, the CCR4-NOT deadenylase complex, and translation initiation factors. RNA sequencing defined mRNAs associated with both LIN-41 and OMA-1, as well as sets of mRNAs associated with either LIN-41 or OMA-1. Genetic and genomic evidence suggests that GLD-2, which is a component of LIN-41 RNPs, stimulates the efficient translation of many LIN-41-associated transcripts. We analyzed the translational regulation of two transcripts specifically associated with LIN-41 that encode the RNA regulators SPN-4 and MEG-1. We found that LIN-41 represses translation of spn-4 and meg-1, whereas OMA-1 and OMA-2 promote their expression. Upon their synthesis, SPN-4 and MEG-1 assemble into LIN-41 RNPs prior to their functions in the embryo. This study defines a translational repression-to-activation switch as a key element of cytoplasmic maturation.