2,5-二氯硝基苯的SOS突变及其分子机制

SOS Mutagenesis of 2,5-Dichloronitrobenzo| and its Molecular Mechanisms

2,5-二氯硝基苯对S.typhimurium(his^-)有回复突变作用,质粒pKM_(101)和pSK_(1002)能增强其突变效应。它在含umu-lac融合基因的S.typhimurium和E.coli上亦能诱导SOS反应,通过umuC介导以及依lexA和/或recA旁路调节机制可致SOS突变形成。因此,它是一种新的SOS诱变剂。

2,5-Dichloronitrobezol ( 2,5-DCNB, 50-2500μg/ml ) caused reverse mutation in S. cyphimurium (his-); its mutagenesis enhancing effect occured by plasmid pKMl0l and pSK1002. 2,5-DCNB( 10-1000μg/ml ) also was able to induce SOS responses in S. typhimurium and .E.coli containing a umu-lac fusion gene and to increase the level of the constitutive expressior of the SOS network genes in E.coli supplemented lexA-. It is supposed that the mutagenesis of 2,5-DCNB had relation to SOS responses and 2,5-DCNB led to SOS mutagenesis, which mechanisms were mediated by umuC gene and regulated by lexA and/or recA gene bypass in bacterial cells. Therefore 2,5-DCNB is a new SOS mutagen.