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Structural basis for the activation of the C. elegans noncanonical cytoplasmic poly(A)-polymerase GLD-2 by GLD-3

Nakel, Katharina, Bonneau, Fabien, Eckmann, Christian R., Conti, Elena
Proceedings of the National Academy of Sciences of the United States of America 2015 v.112 no.28 pp. 8614-8619
Caenorhabditis elegans, messenger RNA, neurons, oocytes, substrate specificity, translation (genetics)
The efficient translation of the vast majority of eukaryotic mRNAs requires the presence of a poly(A) tail. Although the poly(A) tail was originally thought of as a stable modification, it is now clear that it is much more dynamic. Poly(A) tails can be shortened by deadenylases, leading to mRNA decay or translational repression. The short poly(A) tails of translationally inactive mRNAs can also be reextended by cytoplasmic noncanonical poly(A) polymerases, activating their translation. This mechanism of translational control is found predominantly in metazoan oocytes and neurons and is mediated by germ-line development defective (GLD)-2. Here, we report the molecular mechanism with which Caenorhabditis elegans GLD-2 is activated by GLD-3, a homologue of Bicaudal-C, and identify the unusual substrate specificity of this class of noncanonical poly(A) polymerases.