Worm Breeder's Gazette 14(2): 78 (February 1, 1996)
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.
Laboratory of Molecular Biology, University of Wisconsin, Madison, WI 53706We are interested in studying various aspects of asymmetric cell cleavage, among them the mechanism that determines the position of cell cleavage planes, during the well characterized embryonic divisions of C. elegans. A genetic screen capable of isolating a large collection of conditional cell division mutants has been devised. Isolation of these mutants relies upon expression of two developmental-stage specific phenotypes. Lethality is expected among the progeny of a mutant adult shifted to the nonpermissive temperature as the embryonic cell divisions should fail, while a viable but sterile uncoordinated phenotype is expected of an animal shifted following embryogenesis, as the divisions of the postembryonically-developing gonad and ventral nervous system should be affected. Specifically, the screening format involves a selection method to generate pools of mutants that exhibit a conditional embryonic lethal phenotype.! These pools are then screened for the presence of a postembryonic sterile uncoordinated phenotype. To date an estimated 50,000 haploid genomes have been screened and 29 mutant lines that meet these criteria have been isolated. Preliminary analysis indicates that embryos from many of these mutant lines exhibit obvious cytological defects including defects in cytokinesis, centrosome activity, and spindle alignment. A summary of mutants with known cytological defects is presented below. We are continuing to characterize these mutants as well as isolate additional mutants.
Mutation Map position Cytological defect oj2ts V Defective polar body formation oj5ts I Cytokinesis defective /spindle abnormal oj7ts II Centrosome duplication /separation defective oj8ts - Multinucleate blastomeres oj10ts - Multinucleate blastomeres oj14ts I Abnormal spindle alignment oj18ts - Abnormal spindle alignment oj29ts - Putative centrosome duplication /separation defective