RexAB proteins of bacteriophage lambda enhance the effect of photolyase-dimer complexes on lacZ gene expression in Escherichia coli.

Important note: Information in this article was accurate in 1992. The state of the art may have changed since the publication date.

RexAB proteins of bacteriophage lambda enhance the effect of photolyase-dimer complexes on lacZ gene expression in Escherichia coli.

Mol Gen Genet. 1992 Feb;231(3):480-4. Unique Identifier : AIDSLINE MED/92167969
Li BH; Kwasniewski M; Kirchner J; Bockrath R; Indiana University School of Medicine, Indianapolis 46202.

Abstract: Expression of the lacZ gene in Escherichia coli is inactivated by exposure to ultraviolet light (UV). Inactivation is exceptionally effective when cells contain amplified levels of DNA photolyase (which forms complexes with pyrimidine dimers in the absence of light for actual photoreversal) and a lambda prophage. Without amplified photolyase, the lambda prophage or both, inactivation rates are similar and much lower. UV-inactivation of lacZ gene expression in the presence of both amplified photolyase and lambda is even more effective if lambda cI857 is used in place of the wildtype prophage but is wholly unexceptional if the prophage carries defects in the lambda genes rexA or rexB. When Rex AB proteins are provided by expression from a plasmid and the cell also contains amplified photolyase, exceptional inactivation rates again obtain; in fact inactivation is most effective under these conditions. The data are considered to reveal a role for Rex AB proteins, which mediate superinfection exclusion, in the exceptional inactivation of gene expression by photolyase bound to pyrimidine dimers in DNA. Photolyase-dimer complexes may mimic the structure of certain complexes that arise during phage development and thus influence Rex A and/or B proteins, thereby shutting down cell metabolism.

Keywords: beta-Galactosidase/*GENETICS Bacteriophage lambda/*METABOLISM Dose-Response Relationship, Radiation DNA Photolyase/*METABOLISM Escherichia coli/ENZYMOLOGY/*GENETICS/RADIATION EFFECTS *Gene Expression Regulation, Bacterial/RADIATION EFFECTS *Gene Expression Regulation, Enzymologic/RADIATION EFFECTS Gene Products, rex/*METABOLISM *Genes, Structural, Bacterial/RADIATION EFFECTS Macromolecular Systems Support, U.S. Gov't, P.H.S. Ultraviolet Rays Viral Proteins/*METABOLISM JOURNAL ARTICLE
920630
M9260195

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