Conservation of the C.elegans tra-2 3'UTR translational control.

The Caenorhabditis elegans sex-determination gene, tra-2, is translationally regulated by two 28 nt elements (DREs) located in the 3'UTR that bind a factor called DRF. This regulation requires the laf-1 gene activity. We demonstrate that the nematode Caenorhabditis briggsae tra-2 gene and the human oncogene GLI are translationally regulated by elements that are functionally equivalent to DREs. Here, we rename the DREs to TGEs (tra-2 and GLI elements). Similarly to the C.elegans tra-2 TGEs, the C.briggsae tra-2 and GLI TGEs repress translation of a reporter transgene in a laf-1 dependent manner. Furthermore, they regulate poly(A) tail length and bind DRF. We also find that the C.elegans TGEs control translation and poly(A) tail length in C.briggsae and rodent cells. Moreover, these same organisms contain a factor that specifically associates with the C.elegans TGEs. These findings are consistent with the TGE control being present in C.briggsae and rodent cells. Three lines of evidence indicate that C.briggsae tra-2 and GLI are translationally controlled in vivo by TGEs. First, like C.elegans tra-2 TGEs, the C.briggsae tra-2 and GLI TGEs control translation and poly(A) tail lengths in C.briggsae and rodent cells, respectively. Second, the same factor in C.briggsae and mammalian cells that binds to the C.elegans tra-2 TGEs binds the C.briggsae tra-2 and GLI TGEs. Third, deletion of the GLI TGE increases GLI's ability to transform cells. These findings suggest that TGE control is conserved and regulates the expression of other mRNAs.