Wn. Chen et al., THE CDC42 HOMOLOG FROM CAENORHABDITIS-ELEGANS - COMPLEMENTATION OF YEAST MUTATION, The Journal of biological chemistry, 268(18), 1993, pp. 3280-3285
A Caenorhabditis elegans cDNA encoding a homologue of the p21 ras-rela
ted CDC42, designated as CDC42Ce, was isolated from a nematode mixed s
tage cDNA library. The encoded protein of 188 amino acid residues has
85% identity to both human G25K and CDC42Hs and 79 and 76% identity to
the yeast CDC42Sp and CDC42Sc proteins, respectively. The CDC42Ce cDN
A maps to a position on C. elegans chromosome II in close proximity to
lin-26, a cell lineage gene. The CDC42Ce cDNA hybridizes to 2- and 1.
5-kilobase mRNAs. Their expression is developmentally regulated with h
ighest levels at the embryonic stage, decreasing progressively during
development except for an increase of the more abundant 1.5-kilobase m
RNA at the L3 stage. The glutathione S-transferase/CDC42Ce fusion prot
ein expressed in Escherichia coli displays both GTP binding and intrin
sic GTPase activities. The GTPase activity of CDC42Ce is moderately st
imulated by human n-chimaerin, a GTPase-activating protein for the rel
ated p21 rac1. The CDC42Ce protein complements the temperature-sensiti
ve lethal mutation cdc42-1 in yeast Saccharomyces cerevisiae. These da
ta suggest that CDC42Ce is the C. elegans homologue of the yeast CDC42
. The developmental expression pattern of mRNA and is biochemical prop
erties of its encoded protein which are closely related to CErac1 sugg
est that the two p21s might be involved in related biological processe
s.