K252a compound induced multiple anchor cells in N2 Hermaphrodites Mitsunobu Hara* and Min Han Dept. of MCD Biology, University of Colorado at Boulder, CO 80309 *Present address: Tokyo Research Lab. Kyowa Hakko, Machida, Tokyo 194, JAPAN K252a was originally discovered as a potent inhibitor of cyclic nucleotide - dependent protein kinases and protein kinase C (Kase et al. B.B.R.C. 142, 436, 1987). It has recently been reported that K252a is a potent and selective inhibitor of NGF receptor / trk kinase (Tapley et al. Oncogene 7, 371, 1992). We have examined the effect of K252a on N2 hermaphrodites, and found that it induces sterile and uncoordinated phenotypes at 18 to 35 nmol of drug / plate. In order to gain further insight into the drug-induced phenotype, we studied K252a-treated worms under nomarski optics and found that K252a induced two or three anchor cells in N2 worms in a dose dependent manner, suggesting that K252a affects the VU-AC decision of Zl.ppp and Z4.aaa cells in such a way that those cells both adopt the AC fate. K252a has no effect on
lin-12(d, nl 37) . That is,
lin-12(nl 37J has no anchor cell and has multiple pseudovulvae even in the presence of 3Snmol of K252a. It is therefore likely that the inhibitory target of K252a might be upstream of
lin-12 . Iet- 60(gf, nl O46) is resistant to K252a. K252a(35nmol)-treated
let-60(nlO46) is fertile and is not-uncoordinated. Furthermore, 95% of
let-60(nl O46J have 1 anchor cell in the presence of high concentrations of K252a. In mammalian neural cells such as rat pheochromocytoma PC12 cells, ras functions downstream of the NGF-receptor. Supposing that the inhibitory target of K252a would be an NGF-receptor in C. elegans, the above result would imply that
let-60 could function downstream of the NGF receptor of C. elegans. Toward understanding the molecular target of K252a in C elegans, we screened for K252a-resistant strains, and isolated one resistant mutant,
ku104.
ku104 is completely resistant to 35 nmol of K252a. Genetic mapping of
ku104 is in progress. We are also trying to isolate K252a-sensitive mutants with the aim of isolating K252a-sensitive alleles of the C elegans NGF-receptor.