cdh-3 encodes a member of the cadherin superfamily. We have previously reported the determination of the expression pattern of
cdh-3 in embryos undergoing morphogenesis, as well as the isolation of a deletion allele of
cdh-3 (WBG 13 (2), 76, 1994; 1995 Meeting Abstracts, #416). We have continued our analysis of
cdh-3 expression using a GFP reporter construct and have further characterized the phenotype resulting from the
pk87 deletion allele. Expression of the
cdh-3::GFP reporter construct is confined to ectodermally derived cells. We observe expression, beginning just prior to the start of embryonic morphogenesis, in the seam cells, both arcade cells, F, U, the excretory cell, and
hyp10 and
hyp11. Expression in these cells continues throughout postembryonic development, with the exception of
hyp10,
hyp11 and the excretory cell; expression in these cells continues only into the L1. During the L3 stage we see
cdh-3::GFP expression in the anchor cell and the invaginating vulval epidermis, continuing throughout the development of the vulva. At the same time we also see expression in the VC neurons and the two HSNs. More careful examination of animals homozygous for the
pk87 mutation revealed abnormalities in the morphogenesis of
hyp10 (see table). These defects can be rescued by a wild-type copy of
cdh-3 and are consistent with the expression of
cdh-3::GFP in this cell during the period that it is undergoing a change in cell shape. However, we have not been able to detect any other defects in
pk87 homozygotes. The absence of defects in the other cells that express
cdh-3 reporter constructs hints that other genes may substitute for
cdh-3 function. Future work will address this possibility, both by isolating mutations in the other cdh genes that have been identified and by carrying out screens for mutations that cause additional phenotypes in a
cdh-3(
pk87) background. ____________________________________________________________________
hyp10 morphology# ____________________________________________________________________ Genotype N wild-type abnormal ____________________________________________________________________
cdh-3(+) 115 100% 0.0%
cdh-3(
pk87) 170 24% 76.0%
cdh-3(
pk87; pkIs243)* 112 97% 2.5% ____________________________________________________________________ # Abnormalities include ectopic protrusions as well as complete failure to elongate. * Strain carrying an integrated array of
cdh-3(+).