Gussin G N, Brown S, Matz K
Department of Biology, University of Iowa, Iowa City 52242.
Genetics. 1987 Oct;117(2):173-9. doi: 10.1093/genetics/117.2.173.
A PRM-cI-lacZ fusion inserted into the b2 region of bacteriophage lambda was used to isolate mutations affecting expression of both the lambda cI gene and the lacZ gene. One such mutation, a change in the cI initiator codon from AUG to AUA, reduces immunity of a lambda prophage to superinfection, and causes a 60-70% reduction in beta-galactosidase synthesis, even when repressor is supplied in trans. The effect of the mutation on lacZ gene expression is eliminated in a rho- bacterial strain, and the mutation has no effect on transcription initiated at PRM in vitro. Therefore, the effects of the mutation are due to premature p-dependent termination of transcription in the absence of translation of the cI gene, as if the mutation were a nonsense polar mutation.
将一个PRM-cI-lacZ融合基因插入噬菌体λ的b2区域，用于分离影响λ cI基因和lacZ基因表达的突变。其中一个这样的突变，即cI起始密码子从AUG变为AUA，降低了λ原噬菌体对超感染的免疫性，即使在反式提供阻遏物的情况下，也会导致β-半乳糖苷酶合成减少60-70%。该突变对lacZ基因表达的影响在rho-细菌菌株中消除，并且该突变对体外从PRM起始的转录没有影响。因此，该突变的影响是由于在cI基因未翻译的情况下，转录提前发生p依赖性终止，就好像该突变是一个无义极性突变。
