A Genetic Screen for Temperature-Sensitive Cell-Division Mutants of Caenorhabditis elegans

• Published in: Genetics (Austin) Vol. 149; no. 3; pp. 1303 - 1321
• Main Authors: O'Connell, Kevin F, Leys, Charles M, White, John G
• Format: Journal Article
• Language: English
• Published: United States Genetics Soc America 01.07.1998; Genetics Society of America
• Subjects: Animals; Caenorhabditis elegans - cytology; Caenorhabditis elegans - drug effects; Caenorhabditis elegans - genetics; Cell division; Cell Division - genetics; Chromosome Mapping; Crosses, Genetic; Deoxyribonucleic acid; DNA; Ethyl Methanesulfonate - pharmacology; Genetic Complementation Test; Genetic Testing; Genetics; Molecular biology; Mutagenesis; Mutation; Phenotype; Spindle Apparatus - genetics; Spindle Apparatus - ultrastructure; Temperature
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/149.3.1303

A novel screen to isolate conditional cell-division mutants in Caenorhabditis elegans has been developed. The screen is based on the phenotypes associated with existing cell-division mutations: some disrupt postembryonic divisions and affect formation of the gonad and ventral nerve cord-resulting in sterile, uncoordinated animals-while others affect embryonic divisions and result in lethality. We obtained 19 conditional mutants that displayed these phenotypes when shifted to the restrictive temperature at the appropriate developmental stage. Eighteen of these mutations have been mapped; 17 proved to be single alleles of newly identified genes, while 1 proved to be an allele of a previously identified gene. Genetic tests on the embryonic lethal phenotypes indicated that for 13 genes, embryogenesis required maternal expression, while for 6, zygotic expression could suffice. In all cases, maternal expression of wild-type activity was found to be largely sufficient for embryogenesis. Cytological analysis revealed that 10 mutants possessed embryonic cell-division defects, including failure to properly segregate DNA, failure to assemble a mitotic spindle, late cytokinesis defects, prolonged cell cycles, and improperly oriented mitotic spindles. We conclude that this approach can be used to identify mutations that affect various aspects of the cell-division cycle.