In Caenorhabditis elegans, Ras/ERK and Wnt/beta-catenin signaling pathways cooperate to induce P12 and vulval cell fates in a Hox-dependent manner. Here we describe
eor-1 and
eor-2, two new positively acting nuclear components of the Ras and Wnt pathways.
eor-1 and
eor-2 act downstream or in parallel to ERK and function redundantly with the Mediator complex gene
sur-2 and the functionally related gene
lin-25, such that removal of both
eor-1/eor-2 and
sur-2/lin-25 mimics the removal of a main Ras pathway component. Furthermore, the
eor-1 and
eor-2 mutant backgrounds reveal an essential role for the Elk1-related gene
lin-1.
eor-1 and
eor-2 also act downstream or in parallel to
pry-1 Axin and therefore act at the convergence of the Ras and Wnt pathways.
eor-1 encodes the ortholog of human PLZF, a BTB/zinc-finger transcription factor that is fused to RARalpha in acute promyelocytic leukemia.
eor-2 encodes a novel protein. EOR-1/PLZF and EOR-2 appear to function closely together and cooperate with Hox genes to promote the expression of Ras- and Wnt-responsive genes. Further studies of
eor-1 and
eor-2 may provide insight into the roles of PLZF in normal development and leukemogenesis.