Liu S K, Tessman I
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
J Bacteriol. 1990 Oct;172(10):6135-8. doi: 10.1128/jb.172.10.6135-6138.1990.
Repair of UV-irradiated bacteriophage in Escherichia coli by Weigle reactivation requires functional recA+ and umuD+C+ genes. When the cells were UV irradiated, the groE heat shock gene products, GroES and GroEL, were needed for at least 50% of the Weigle reactivation of the single-stranded DNA phage S13. Because of repression of the umuDC and recA genes, Weigle reactivation is normally blocked by the lexA3(Ind-) mutation (which creates a noncleavable LexA protein), but it was restored by a combination of a high-copy-number umuD+C+ plasmid and a UV dose that increases groE expression. Maximal reactivation was achieved by elevated amounts of the Umu proteins, which was accomplished in part by UV-induced expression of the groE genes. By increasing the number of copies of the umuD+C+ genes, up to 50% of the normal amount of reactivation of S13 was achieved in an unirradiated recA+ host.
通过韦格尔复活作用在大肠杆菌中修复紫外线照射的噬菌体需要功能性的recA⁺和umuD⁺C⁺基因。当细胞受到紫外线照射时，单链DNA噬菌体S13至少50%的韦格尔复活作用需要groE热休克基因产物GroES和GroEL。由于umuDC和recA基因的抑制作用，韦格尔复活作用通常被lexA3(Ind⁻)突变（产生不可裂解的LexA蛋白）阻断，但通过高拷贝数的umuD⁺C⁺质粒和增加groE表达的紫外线剂量的组合可使其恢复。通过增加Umu蛋白的量实现了最大程度的复活，这部分是通过紫外线诱导groE基因的表达来完成的。通过增加umuD⁺C⁺基因的拷贝数，在未照射的recA⁺宿主中可实现高达S13正常复活量50%的复活。
