[Genetic and epigenetic effects of lgl-tumor suppressor mutations on longevity under heat stress]

Human populations are polymorphic for risk factor mutations predisposing to diseases and cancer. The evolutionary conservative gene, tumor suppressor lethal (2) giant larvae (lgl), whose null variants are widespread in natural Drosophila populations, can be used as a model to study this phenomenon. We studied the effect of deletion and insertion mutant alleles of the lgl gene on the survival and longevity of their carriers depending on the genotype, cross direction, and action of permanent or impulse temperature stress. Under constant temperature stress, the viability and longevity of lgl/+ deletion heterozygotes increased compared to the control flies carrying two alleles of this gene. This haploid effect was maternally mediated. Exposure of deletion heterozygotes at successive oogenesis stages to moderate impulse temperature stress affected progeny survival in a similar way. The effect of impulse heating at the preembryonal stage was bidirectional: positive in the case of impulse warming of mature eggs and negative during egg differentiation. However, in both cases, deletion of one allele of the tumor suppressor gene in lgl/+ females increased survival of the next generation and delayed senescence. These data were compared to similar epigenetic transgeneration effects reported earlier for humans.