Two conserved regulatory cytoplasmic poly(A) polymerases, GLD-4 and GLD-2, regulate meiotic progression in C. elegans.

ABSTRACT: Translational regulation is heavily employed during developmental processes to control the timely accumulation of proteins independently of gene transcription. In particular, mRNA poly(A) tail metabolism in the cytoplasm is a key determinant for balancing an mRNA's translational output and its decay rate. Noncanonical poly(A) polymerases (PAPs), such as germline development defective-2 (GLD-2), can mediate poly(A) tail extension. Little is known about the regulation and functional complexity of cytoplasmic PAPs. Here we report the discovery of Caenorhabditis elegans GLD-4, a cytoplasmic PAP present in P granules that is orthologous to Trf4/5p from budding yeast. GLD-4 enzymatic activity is enhanced by its interaction with GLS-1, a protein associated with the RNA-binding protein GLD-3. GLD-4 is predominantly expressed in germ cells, and its activity is essential for early meiotic progression of male and female gametes in the absence of GLD-2. For commitment into female meiosis, both PAPs converge on at least one common target mRNA-i.e., gld-1 mRNA-and, as a consequence, counteract the repressive action of two PUF proteins and the putative deadenylase CCR-4. Together our findings suggest that two different cytoplasmic PAPs stabilize and translationally activate several meiotic mRNAs to provide a strong fail-safe mechanism for early meiotic progression.

SUBMITTER: Schmid M 

PROVIDER: S-EPMC2666339 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature