The
lin-29 gene encodes two isoforms of a (Cis) 2 -(His) 2 zinc finger transcription factor that are involved in several developmental events that occur at the transition from the fourth larval stage (L4) to the adult in the nematode Caenorhabditis elegans . LIN-29 has been shown to participate in coordinating the development of the hypodermal syncytium. In
lin-29 mutants the number of vulval cell divisions is normal but the vulva appears to evert incorrectly resulting in a protruding vulva phenotype indicating that
lin-29 may also play a role in the developmental coordination of the hermaphrodite vulva, a significantly more complex organ than the hypodermis. Several genes have been shown to be crucial for proper vulval cell fate execution. The spatial and temporal expression patterns of these marker genes in the primary and secondary lineages of the vulva are promising tools for identifying LIN-29 functionality. The expression of the vulval cell markers
lin-11::gfp (LIM homeodomain transcription factor) and
egl-17::gfp (fibroblast growth factor) is either reduced or abolished in a
lin-29 mutant background. We are exploring a possible regulatory pathway involving these three genes during vulval differentiation and morphogenesis. T04B2. 6 is an uncharacterized gene that is expressed in the vulB1, vulB2 and vulD cells of the adult vulva. The expression of T04B2.6::yfp commences later than that of all other cell fate markers regulated by
lin-29 , its expression, however, is unexpectedly abolished in a lin- 29 background. We speculate that lin- 29 might indirectly regulate T04B2. 6. A screen using RNA interference to all the known and putative transcription factors in the C. elegans genome was conducted to identify transcription factors necessary for T04B2.6 expression. This screen revealed five transcription factors that may interact with LIN-29 in developmental coordination of the vulva.