The STAR protein, GLD-1, is a translational regulator of sexual identity in Caenorhabditis elegans

Open Access
Publisher Website
Google Scholar
Abstract
The Caenorhabditis elegans sex determination gene, tra‐2 , is translationally regulated by elements in the 3′‐untranslated region called TGEs. TGEs govern the translation of mRNAs in both invertebrates and vertebrates, indicating that this is a highly conserved mechanism for controlling gene activity. A factor called DRF, found in worm extracts binds the TGEs and may be a repressor of translation. Using the yeast three‐hybrid screen and RNA gel shift analysis, we have found that the protein GLD‐1, a germline‐specific protein and a member of the STAR family of RNA‐binding proteins, specifically binds to the TGEs. GLD‐1 is essential for oogenesis, and is also necessary for spermatogenesis and inhibition of germ cell proliferation. Several lines of evidence demonstrate that GLD‐1 is a translational repressor acting through the TGEs to repress tra‐2 translation. GLD‐1 can repress the translation of reporter RNAs via the TGEs both in vitro and in vivo , and is required to maintain low TRA‐2A protein levels in the germline. Genetic analysis indicates that GLD‐1 acts upstream of the TGE control. Finally, we show that endogenous GLD‐1 is a component of DRF. The conservation of the TGE control and the STAR family suggests that at least a subset of STAR proteins may work through the TGEs to control translation.