Worm Breeder's Gazette 12(4): 39 (October 1, 1992)

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.

Characterization and Cloning the unc-41 Gene

S.Harada, R.Hosono

Department of Biochemistry. School of Medicine, Kanazawa University, Kanazawa, Ishikawa 920 Japan

We are interested in genes affecting acetylcholine levels in C. elegans. We started detailed analyses of gene unc-41 whose mutations cause abnormal acetylcholine accumulation. J.Hodgkin (MRC. Cambridge) kindly provided us with the unc-41 gene mutant alleles. We studied phenotypes of ten unc-41 alleles, with regard to acetylcholine levels, response to inhibitors of acetylcholinesterase and development. Eight unc-41 mutant alleles had abnormal acetylcholine levels, in addition to resistance to trichlorfon, a potent acetylcholinesterase inhibitor and was abnormal in the post-embryonic development. The remaining two alleles, e1162 and e554 had norrnal acetylcholine levels; the latter is normal but the former is abnormal in the drug sensitivity and development. Complementation tests were carried out on the drug sensitivity and development. On the developmental phenotype, any combination of unc-41 alleles failed to complement each other. On resistance to trichlorfon, e554 complemented the remaining alleles tested, indicating that two separable regions affecting drug resistance are present within the unc-41 gene. To test the ability of the unc-41 mutants to release acetylcholine, we are currently attempting to establish an in vitro assay system. By using the Tc1 -inducedmutation (Hosono et al., Zool.Sci. 6 697 '89), the 3.8 kb BglII fragment has been cloned. The clone was sent to A.Coulson (MRC, Cambridge) to identify cosmid clones covering the unc-41 gene. The unc-18 gene, belonging to the gene group has been cloned (Hosono et al., J.Neurochem, 58 1517 '92) and the complete cDNA sequence has been determined (K.G.Ando et al., submitted to press). The predicted unc-18 protein was seen significant homology with several yeast proteins that function in protein transport from the endoplasmic reticulum to the Golgi apparatus and at the post-Golgi. Antibodies raised against the unc-18 protein stained axons of motor neurons. From these results, we conclude that the unc-18 gene product functions in protein transport at the motor neurons.

Literature Cited:

Hosono et al., Zool.Sci. 6 697 '89.

K.G.Ando et al., submitted to press.