RNA-Regulated TRA-1 nuclear export controls sexual fate.

TRA-1, a member of the GLI family of transcription factors, is required for C. elegans female development. We find that TRA-1 has a sex-specific distribution consistent with its role in female development: nuclear TRA-1 is higher in hermaphrodite intestines and in specific germline regions than in males. TRA-1 patterns rely on nuclear export since treatment with leptomycin B, a CRM1-dependent export inhibitor, increases nuclearTRA-1 in males. TRA-1 export requires TRA-1 binding to the tra-2 3' untranslated region (3' UTR), as disruption of binding increases nuclear TRA-1 and female development. Our data are consistent with coexport of a TRA-1/tra-2 mRNA complex reducing TRA-1 nuclear activity, and identify an interesting RNA-based mechanism for controlling transcriptional activity and cell fate determination.