Abstract
Previous studies indicated that these genetic elements could be involved in the regulation of lysogenization and prophage induction processes. The effects were dramatic in Shiga toxin-converting phage Φ24(B) after treatment with oxidative stress-inducing agent, hydrogen peroxide, while they were less pronounced in bacteriophage λ and in both phages irradiated with UV. The hydrogen peroxide-caused prophage induction was found to be RecA-dependent. Importantly, in hydrogen peroxide-treated E. coli cells lysogenic for either λ or Φ24(B), deletion of the exo-xis region resulted in a significant decrease in the levels of expression of the S.O.S. regulon genes. Moreover, under these conditions, a dramatic decrease in the levels of expression of phage genes crucial for lytic development (particularly xis, exo, N, cro, O, Q, and R) could be observed in Φ24(B)-, but not in λ-bearing cells. We conclude that genes located in the exo-xis region are necessary for efficient expression of both host S.O.S regulon in lysogenic bacteria and regulatory genes of Shiga toxin-converting bacteriophage Φ24(B).
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Amino Acid Sequence
-
Bacterial Proteins / chemistry
-
Bacterial Proteins / metabolism
-
Bacteriophage lambda / drug effects
-
Bacteriophage lambda / metabolism
-
Bacteriophage lambda / radiation effects
-
Escherichia coli / drug effects
-
Escherichia coli / genetics
-
Escherichia coli / radiation effects
-
Gene Expression Regulation, Bacterial / drug effects
-
Gene Expression Regulation, Bacterial / radiation effects
-
Hydrogen Peroxide / pharmacology
-
Lysogeny / drug effects
-
Lysogeny / radiation effects
-
Molecular Sequence Data
-
Oxidative Stress / drug effects
-
Oxidative Stress / genetics*
-
Oxidative Stress / radiation effects
-
Polymerase Chain Reaction
-
Prophages / drug effects
-
Prophages / metabolism*
-
Prophages / radiation effects
-
Rec A Recombinases / metabolism
-
Regulatory Sequences, Nucleic Acid / genetics*
-
Regulon / genetics
-
SOS Response, Genetics / drug effects
-
SOS Response, Genetics / genetics
-
Sequence Alignment
-
Serine Endopeptidases / chemistry
-
Serine Endopeptidases / metabolism
-
Shiga Toxin / metabolism*
-
Ultraviolet Rays
-
Virus Activation / drug effects
-
Virus Activation / radiation effects
Substances
-
Bacterial Proteins
-
LexA protein, Bacteria
-
Shiga Toxin
-
Hydrogen Peroxide
-
Rec A Recombinases
-
Serine Endopeptidases