DNA polymerase β (pol β) cDNA of rat fused to an enhancer-promoter region plus a poly(A) signal sequence of actin 5C gene of
Drosophila (abbreviated
pol β) was transferred to the
Drosophila genome. Three of four constructed transgenic strains possessing transgene
pol β on different chromosomes were studied. Levels of the pol β transcript and those of the polymerization activity of pol β were markedly elevated in cultured cells transfected with
polβ-bearing vectors as well as in embryos of the transgenic strains. The popular idea that DNA polymerase β participates in DNA repair was not supported by the observation that a pair of a normal and a
polβ strain, and the other pair of a
mei-9 mei-41 (DNA-repair deficient double mutations) strain and a
polβ
mei-9 mei-41 strain, showed no difference in survival within each pair after treatment with ultraviolet light, methylmethane sulfonate and mitomycin C. The other idea that DNA polymerase β participates in recombination was supported by the findings that spontaneous frequency of recombination, either meiotic or mitotic, is significantly higher in a transgenic
polβ strain than in a non-transgenic strain. The enhanced recombination frequency in the
polβ strain may, however, reflect an indirect effect of over-produced pol β proteins on chromosomal stability. Whatever the direct effect of rat pol β is, the transgenic
polβ flies will be useful for study of the physiological role of pol β and the mechanism of recombination.
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