Nus A参与λ噬菌体tI基因的转录终止过程。

Nus A is involved in transcriptional termination on lambda tI.

作者信息

Bermúdez-Cruz R M, Chamberlin M J, Montañez C

机构信息

Departmento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., Mexico City, D.F.C.P., Mexico.

出版信息

Biochimie. 1999 Jul;81(7):757-64. doi: 10.1016/s0300-9084(99)80134-5.

DOI:10.1016/s0300-9084(99)80134-5

PMID:10492023

Abstract

The transcriptional terminator tI generates the 3'end of the integrase (int) gene transcript that is read from the lambda PI promoter in lambda phage. We have studied the factors that affect transcription termination in vitro and in vivo at the lambda tI terminator. In vitro transcriptional studies showed that tI is about 80% efficient in the presence of purified NusA protein, whereas it is only about 50% efficient in its absence. In vivo studies, where the readthrough transcript of lambda tI was measured by quantitative dot blot analysis, gave about 80% efficiency in wild-type strains, but only 60% in the nusA1 mutant strain at non-permissive temperatures. These results support the idea that termination at lambda tI in vivo involves interaction with the NusA factor.

摘要

转录终止子tI产生整合酶（int）基因转录本的3'末端，该转录本从λ噬菌体中的λPI启动子起始转录。我们研究了影响λ噬菌体tI终止子在体外和体内转录终止的因素。体外转录研究表明，在纯化的NusA蛋白存在的情况下，tI的终止效率约为80%，而在其不存在时，终止效率仅约为50%。在体内研究中，通过定量斑点印迹分析测量λ噬菌体tI的通读转录本，在野生型菌株中的终止效率约为80%，但在非允许温度下的nusA1突变菌株中仅为60%。这些结果支持这样一种观点，即λ噬菌体tI在体内的终止涉及与NusA因子的相互作用。