文章基本信息

标题：DNA sequence of regulatory region for integration gene of bacteriophage λ
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作者：Judith Abraham ; Desmond Mascarenhas ; Robert Fischer 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1980
卷号：77
期号：5
页码：2477-2481
DOI：10.1073/pnas.77.5.2477
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The cII and cIII proteins specified by bacteriophage {lambda} direct the lysogenic response to infection through the coordinate establishment of repression and integration of the viral DNA. The regulatory activity of cII/cIII involves positive regulation of two promoter sites: the pE promoter, turning on expression of the cI protein that maintains lysogeny, and the pI promoter, activating synthesis of the Int protein for integrative recombination. Regulation of the pI promoter provides for differential expression of the Int protein with respect to the excision-specific Xis protein from the closely linked int and xis genes. We have determined the DNA sequence of the pI promoter region for wild-type {lambda} DNA and for two classes of mutations: intc mutations, which result in a high rate of Int synthesis in the absence of cII, and deletion mutations, some of which eliminate cII-activated expression of the int gene. We find a sequence with considerable homology (11 of 15 bases) to a "typical" (computer-generated) promoter sequence, adjacent to a region with striking homology (11 of 14 bases) to part of the pE promoter region. This presumed pI sequence overlaps the start of the xis gene and includes the site of two intc point mutations. A cII-insensitive xis+ deletion partially removes the proposed pI sequence; a deletion that leaves the pI sequence intact but terminates 21 bases upstream does not interfere with cII activation of the int gene. From our results and the analysis of the pE region, we suggest that cII acts in the promoter -35 recognition region to facilitate binding by RNA polymerase at the -10 interaction region. Differential expression of the int and xis genes results because the pI transcript lacks the initiation codon for Xis protein synthesis.
关键词：promoter structure ; RNA regulation ; bacteriophage λ cII ; cIII proteins