ISSN:
1617-4623
Keywords:
Photolyase-dimer complexes
;
Lambda genes rexA and rexB
;
Superinfection exclusion
;
Gene expression
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary 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 λ prophage. Without amplified photolyase, the λ prophage or both, inactivation rates are similar and much lower. UV-inactivation of lacZ gene expression in the presence of both amplified photolyase and λ is even more effective if λ cI857 is used in place of the wildtype prophage but is wholly unexceptional if the prophage carries defects in the λ 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00292719
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