Worm Breeder's Gazette 11(4): 51
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
Loss-of-function mutations in daf-4 confer a dauer-constitutive phenotype. Two transposon-tagged alleles of daf-4 have been isolated, and Southern blots probed with the labeled transposon sequence revealed a novel restriction fragment in the mutant DNA that was absent in non-mutant DNA. A transposon-containing fragment was cloned, and sequences flanking the transposon were used to screen Bob Barstead's cDNA library and Chris Link's genomic library. Four overlapping genomic clones and five cDNA clones were isolated. Microinjection of one of the genomic clones into the germline of daf-4 mutants transforms their progeny to wild type. Approximately 1 kb of contiguous cDNA sequence has been determined, and the deduced amino acid sequence shows 30% identity to the C. elegans brane receptor kinase (Georgi et al., 1990, Cell 61: 635) over a 222 amino acid region in the catalytic domain. The deduced amino acid sequence also shares 37% identity with PSK-J3 ( from HeLa cells), a member of the cdc2/CDC28 kinase family over a 107 amino acid region in the catalytic domain. Since genetic interactions suggest that daf-4 acts downstream of the daf-1 receptor, we propose that it mediates the second step in a kinase cascade that normally acts to prevent dauer larva development, and permit growth.