Transcription factors regulating the fate and developmental potential of a multipotent progenitor in Caenorhabditis elegans.

Multipotent stem and progenitor cells have the capacity to generate a limited array of related cell types. The Caenorhabditis elegans somatic gonadal precursors are multipotent progenitors that generate all 143 cells of the somatic gonad, including complex tissues and specialized signaling cells. To screen for candidate regulators of cell fate and multipotency, we identified transcription factor genes with higher expression in somatic gonadal precursors than in their differentiated sister, the head mesodermal cell. We used RNA interference or genetic mutants to reduce the function of 183 of these genes and examined the worms for defects in the somatic gonadal precursor cell fate or the ability to generate gonadal tissue types. We identify 8 genes that regulate somatic gonadal precursor fate, including the SWI/SNF chromatin remodeling complex gene swsn-3 and the Ci/GLI homolog tra-1, which is the terminal regulator of sex determination. Four genes are necessary for somatic gonadal precursors to generate the correct number and type of descendant cells. We show that the E2F homolog, efl-3, regulates the cell fate decision between distal tip cells and the sheath/spermathecal precursor. We find that the FACT complex gene hmg-4 is required for the generation of the correct number of somatic gonadal precursor descendants, and we define an earlier role for the nhr-25 nuclear hormone receptor-encoding gene, in addition to its previously described role in regulating the asymmetric division of somatic gonadal precursors. Overall, our data show that genes regulating cell fate are largely different from genes regulating developmental potential, demonstrating that these processes are genetically separable.