Homozygous eye discs show severe defects in hydroxyurea-induced G2 arrest, with the number of mitotic cells remaining high after treatment, in contrast to wild type.
X-ray irradiation of wild-type third-instar wing imaginal discs induces cell cycle arrest within 1 hour. In contrast, X-ray irradiation of mei-41RT1 mutant larvae fails to induce cell cycle arrest.
Mutant larvae fail to undergo G2 arrest in response to ionizing radiation, in contrast to wild type (assayed by scoring mitotic cells in larval eye-antennal imaginal discs).
Mutant larvae fail to undergo intra-S phase arrest in response to ionizing radiation, in contrast to wild type (assayed by scoring mitotic cells in larval brains).
Mutants are hypersensitive to irradiation, showing only 3.3% eclosion after exposure to 10 Gray (90.2% of wild-type larvae eclose at this dose).
Mutant larvae lack the normal checkpoint response (a steep decline in the number of G2 cells entering mitosis) when irradiated with either 500 or 4000 rad of X rays.
Mutant wing discs do not show cell cycle block after X-ray irradiation (in contrast to wild type), with the number of mitotic cells in mutant irradiated wing discs being similar to the number of mitotic cells in untreated mutant wing discs.
The number of mitotic cells in the mei-41RT1 eye disc is unchanged following irradiation, in contrast to wild-type discs where very few cells are in M phase after irradiation. The morphology of the eye disc and adult eye is normal in unirradiated mei-41RT1 animals.
Homozygotes are sensitive to MMS and show female sterility.
Methyl methanesulfonate sensitive, exposure causes lethality. Frequency of XO males and XXY females suggests high rates of chromosome loss.