紫外線による変異の誘導が不足している大腸菌の変異体の分離と特性評価

AB1157のUVR-B誘導体の約30,000の突然変異誘発クローンのスクリーニングにより、6つのUMU株が得られました。変異体は、UMUA、UMUB、およびUMUCの位置によって3つのグループに分類できます。突然変異UMUAとUMUBは、それぞれ、両方の遺伝子座でレクサおよびRECA遺伝子と変異の近くでマッピングされています。UMUCの軌跡はHEMAとPURBの間であり、この新しい軌跡での突然変異はUV感受性の中程度の増加をもたらします。RecF-Mutantの同質性株の関連特性は、UMUC-の著作物と比較されます。

Mutants of E. coli defective in susceptibility to UV-induction of mutations were isolated by direct screening for their UV nonmutable phenotype (Umu-). Screening of about 30,000 mutagenized clones of a uvr-B derivative of AB1157 yielded six Umu- strains. The mutants can be classified into three groups by the location of the mutations, umuA, umuB and umuC. Mutations umuA and umuB are, respectively, mapped close to lexA and recA genes and mutations at both loci partially reduce UV mutagenesis. The locus of umuC is between hemA and purB and the mutations at this new locus result in a moderate increase of UV sensitivity. The mutation diminishes UV mutagenesis and UV reactivation of phage lambda without affecting the inducibility of phophage lambda nor the inhibition of cell division following UV irradiation. Related properties of an isogenic strain of a recF- mutant are compared with those of umuC-.