%0 Journal Article
%T The roles of EGF and Wnt signaling during patterning of the C. elegans B¦Ã/¦Ä Equivalence Group
%A Adeline Seah
%A Paul W Sternberg
%J BMC Developmental Biology
%D 2009
%I BioMed Central
%R 10.1186/1471-213x-9-74
%X We show that EGF-Ras signaling is required for B¦Ã expression of ceh-13/labial/Hox1. The transcription factors lin-1/ETS and lin-31/Forkhead, functioning downstream of the EGF pathway, as well as sur-2/MED23 (a component of the Mediator complex) also control ceh-13 expression in B¦Ã. In addition, our results indicate that lin-44/Wnt, mom-2/Wnt and lin-17/Fz are necessary to maintain the division of B¦Ã along a longitudinal axis. We also show that dbl-1/dpp acts either in parallel or downstream of EGF pathway to regulate ceh-13/Hox1 expression in B¦Ã. Lastly, we find that a dbl-1/dpp null mutation did not cause any vulval or P12 defects and did not enhance vulval and P12 defects of reduction-of-function mutations of components of the EGF pathway.ceh-13/labial/Hox1 expression in B¦Ã is regulated by the EGF pathway and downstream factors lin-1/ETS lin-31/Forkhead and sur-2/MED23. Wnt signaling is required for proper B¦Ã division, perhaps to orient the B¦Ã mitotic spindle. Our results suggest that dbl-1/dpp is not required for VPC and P12 specification, highlighting another difference among these EGF-dependent equivalence groups.During development, fate specification within equivalence groups (a set of cells with similar potential) often requires extracellular cues provided by surrounding cells [1-5]. The response elicited by a particular signaling pathway is context-specific: the fate acquired by a cell depends on its developmental history (i.e., the genes expressed by a cell) as well as the presence of other external signals. One mechanism by which signaling pathways specify fate is by regulating master control genes that initiate expression of a battery of genes required for a particular fate. Hox genes are a class of master regulators that pattern the anterior-posterior axis of metazoans during embryogenesis. In C. elegans, there is accumulating evidence that different Hox genes are upregulated by Wnt and EGF-Ras signaling in different equivalence groups.EGF and Wnt signal
%U http://www.biomedcentral.com/1471-213X/9/74