TRA-1 regulates the cellular distribution of the tra-2 mRNA in C. elegans

The GLI protein family is involved in several key developmental processes in both vertebrates and invertebrates. The Drosophila GLI protein, Cubitus interuptus (Ci), regulates segment polarity and wing and leg development. In vertebrates, the GLI proteins control neural, lung, bone and gut development. In the nematode Caenorhabditis elegans, the GLI family member TRA-1 is necessary for normal sexual development. GLI, Ci and TRA-1 each contain five zinc-finger domains and bind the identical DNA sequence. Previous analyses are consistent with these proteins being transcription factors. Here we show that TRA-1 can act posttranscriptionally to govern gene activity. Our results indicate that the binding of TRA-1 to the 3' untranslated region of tra-2 regulates the export of tra-2 messenger RNA from the nucleus. The fact that TRA-1 is part of a conserved family of proteins raises the possibility that GLI family members are both transcriptional and post-transcriptional regulators of gene expression.