Ligand-activated transcription factor (By similarity). Positively modulates expression of homeobox protein lin-39, perhaps by binding to the sequence motif 5'-TGAC-3' in regulatory regions of the lin-39 gene, acting in the embryo, and also in the vulval lineage (PubMed:24885717). RNAi-mediated knockdown reduces expression of homeobox protein lin-39 in vulval precursor cells at the larval L3 stage. Extended N-terminus.