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Updated: Aug 26, 2025

Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
Study of Ren, RexA, and RexB Functions Provides Insight Into the Complex Interaction Between Bacteriophage λ and Its
Lynn C Thomason1,2, Donald L Court2
1Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA.
Abstract:
The phage λ rexA and rexB genes are expressed from the P RM promoter in λ lysogens along with the cI repressor gene. RexB is also expressed from a second promoter, P LIT, embedded in rexA. The combined expression of rexA and rexB causes Escherichia coli to be more ultraviolet (UV) sensitive. Sensitivity is further increased when RexB levels are reduced by a defect in the P LIT promoter, thus the degree of sensitivity can be modulated by the ratio of RexA/RexB. Expression of the phage λ ren gene rescues this host UV sensitive phenotype; Ren also rescues an aberrant lysis phenotype caused by RexA and RexB. We screened an E. coli two-hybrid library to identify bacterial proteins with which each of these phage proteins physically interact. The results extend previous observations concerning λ Rex exclusion and show the importance of E. coli electron transport and sulfur assimilation pathways for the phage.
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