Project description:C. elegans GLD-2 forms an active PAP with multiple RNA-binding partners to regulate diverse aspects of germline and early embryonic development. One GLD-2 partner, RNP-8, was previously shown to influence oocyte fate specification. To identify transcripts selectively associated with both GLD-2 and RNP-8, we employ a genomic approach using the method of RNA immunoprecipitation followed by microarray analysis (RIP-chip). We used microarrays to identify mRNAs selectively associated with either GLD-2 or RNP-8.
Project description:C. elegans GLD-2 forms an active PAP with multiple RNA-binding partners to regulate diverse aspects of germline and early embryonic development. One GLD-2 partner, RNP-8, was previously shown to influence oocyte fate specification. To identify transcripts selectively associated with both GLD-2 and RNP-8, we employ a genomic approach using the method of RNA immunoprecipitation followed by microarray analysis (RIP-chip). We used microarrays to identify mRNAs selectively associated with either GLD-2 or RNP-8. Worm extracts were prepared from synchronized adult C. elegans (15 h after L4 stage). For GLD-2 IP, an immoblized anti-GLD-2 antibody was then used to purify the GLD-2 complexes from either wild-type (N2) or gld-2(RNAi) worm extracts. RNA was then extracted from the pellets and analyzed on C.elegans Affymetrix genechip. Four biological replicates were performed, each sample processed in parallel. For RNP-8 IP, an immoblized anti-RNP-8 antibody was then used to purify the RNP-8 complexes from either wild-type (N2) or rnp-8(q784) worm extracts and three biological replicates were performed. For wt or gld-2(RNAi) samples, total RNA was extracted from worm extracts and hybridized on C.elegans Affymetrix genechip.
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:BRAT-associated mRNAs and PUM-associated mRNAs were identified in early Drosophila embryos by RNA co-immunoprecipitation of the endogenous proteins using synthetic antibodies, followed by microarray analysis (RIP-Chip).