Worm Breeder's Gazette 15(5): 28 (February 1, 1999)
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.
|1||Department of Biopysics and Biochemistry, Graduate School of Science, University of Tokyo, Hongo, 113, Japan.|
|2||Molecular Genetics Research Laboratory, University of Tokyo, Hongo, 113, Japan.|
We have isolated twelve C. elegans cDNAs that trans-complemented the fission yeast mes1 mutation, which causes a defect in the second meiotic division (1, 2). Half of these cDNAs encoded cytoskeletal proteins (two alpha-tubulin, two beta-tubulin and two actin genes) suggesting the importance of cytoskeletal rearrengement in meiosisII. We further characterized one of the genes isolated in this screen, which we named kel-1. kel-1 encodes a 618-amino-acid polypeptide that shows similarity with Drosophila Kelch throughout the protein, which is known to be essential for oogenesis. Mammalian NRP/B, which has been implicated in neuronal differentiation also showed overall similarity with KEL-1. These proteins carry a motif called "kelch repeat" which consists of two to seven repeats of ~50 amino acids. KEL-1 also showed weak similarity with C.elegans SPE-26 and Limulus alpha- and beta-Scruin in this motif. Although many kelch repeat-containing proteins have been found from various species, the function of this motif is still unclear except that alpha-Scruin is known to interact with actin. To investigate the function of the kel-1 gene product, animals mutagenized with UV-trimethylpsoralen were screened for deletion alleles and one deletion allele, kel-1(pe201), was isolated. This kel-1 deletion mutant, which lacks most of the polypeptide, arrested at the early larval stage. However, most mutant animals were not dead soon after the arrest. They survived for several days after hatching and their movement and morphology was essentially normal, except that they accumulated granules throughout their bodies. We investigated the localization of KEL-1 using anti-KEL-1 antibodies and a kel-1::GFP reporter. KEL-1 localized to the pharyngeal g1 gland cells at all stages after late embryogenesis. The g1 gland cells have been suggested to play a role in molting and digestion. L1 lethargus and subsequent molting occurred in the kel-1 deletion mutants, although slightly later than control animals. We speculate that the most likely reason for the developmental arrest is that the kel-1 deletion mutants cannot feed effectively. 1. Hayasizaki et al. (1998) Genes to cells 3, 189-202 2. Ohmachi et al. (1998) Midwest worm Meeting Abstract 79