RADIATION-SENSITIVE MUTANTS OF CAENORHABDITIS ELEGANS

[摘要] Nine rad (for abnormal radiation sensitivity) mutants hypersensitive to ultraviolet light were isolated in the small nematode Caenorhabditis elegans . The mutations are recessive to their wild-type alleles, map to four of the six linkage groups in C. elegans and define nine new games named rad-1 through rad-9 . Two of the mutants— rad-1 and rad-2 —are very hypersensitive to X rays, and three— rad-2, rad-3 and rad-4 —are hypersensitive to methyl methanesulfonate under particular conditions of exposure. The hypersensitivity of these mutants to more than one DNA-damaging agent suggests that they may be abnormal in DNA repair. One mutant— rad-5 , a temperature-sensitive sterile mutant—shows an elevated frequency of spontaneous mutation at more than one locus; rad-4 , which shows a cold-sensitive embryogenesis, reduces meiotic X-chromosome nondisjunction tenfold and partially suppresses some but not all mutations that increase meiotic X-chromosome nondisjunction; the viability of rad-6 hermaphrodites is half that of rad-6 males at 25°; and newly mature (but not older) rad-8 hermaphrodites produce many inviable embryo progeny. Meiotic recombination frequencies were measured for seven rad mutants and found to be close to normal.

[学科分类] 医学（综合）