Yet another way that phage λ manipulates its Escherichia coli host: λrexB is involved in the lysogenic–lytic switch. Issue 4 (16th March 2015)

• Record Type: Journal Article
• Authors: Engelberg‐Kulka, Hanna; Kumar, Sathish
• Is Part Of: Molecular microbiology. Volume 96:Issue 4(2015)
• Page Start: 689
• Page End: 693
• Publication Date: 2015-03-16
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12969
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The life cycle of phage λ has been studied extensively. Of particular interest has been the process leading to the decision of the phage to switch from lysogenic to lytic cycle. The principal participant in this process is the λcI repressor, which is cleaved under conditions of DNA damage. Cleaved λcI no longer acts as a repressor, allowing phage λ to switch from its lysogenic to lytic cycle. The well‐known mechanism responsible for λcI cleavage is the SOS response. We have recently reported that the <italic>E</italic><italic>scherichia coli</italic> toxin‐antitoxin <italic>mazEF</italic> pathway inhibits the SOS response; in fact, the SOS response is permitted only in <italic>E</italic><italic>. coli</italic> strains deficient in the expression of the <italic>mazEF</italic> pathway. Moreover, in strains lysogenic for prophage λ, the SOS response is enabled by the presence of λ<italic>rexB</italic>. λRexB had previously been found to inhibit the degradation of the antitoxin MazE, thereby preventing the toxic action of MazF. Thus, phage λ <italic>rexB</italic> gene not only safeguards the prophage state by preventing death of its <italic>E</italic><italic>. coli</italic> host but is also indirectly involved in the lysogenic–lytic switch.</p> </abstract>