Response to UV damage by four Escherichia coli K-12 restriction systems.
To understand the role of restriction in regulating gene flow in bacterial populations, we would like to understand the regulation of restriction enzyme activity. Several antirestriction (restriction alleviation) systems are known that reduce the activity of type I restriction enzymes like EcoKI in vivo. Most of these do not act on type II or type III enzymes, but little information is available for the unclassified modification-dependent systems, of which there are three in E. coli K-12. Of particular interest are two physiological controls on type I enzymes: EcoKI restriction is reduced 2 to 3 orders of magnitude following DNA damage, and a similar effect is seen constitutively in Dam- cells. We used the behavior of EcoKI as a control for testing the response to UV treatment of the three endogenous modification-dependent restriction systems of K-12, McrA, McrBC, and Mrr. Two of these were also tested for response to Dam status. We find that all four resident restriction systems show reduced activity following UV treatment, but not in a unified fashion; each response was genetically and physiologically distinct. Possible mechanisms are discussed.
Kelleher
J E
JE
New England Biolabs, Beverly, Massachusetts 01915.
Raleigh
E A
EA
D001426:Bacterial Proteins / Q000378:metabolism; D002701:Chloramphenicol / Q000494:pharmacology; D004249:DNA Damage; D004262:DNA Restriction Enzymes / Q000235:genetics / Q000378:metabolism; D015280:DNA Restriction-Modification Enzymes / Q000502:physiology*; D004269:DNA, Bacterial / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008780:Methyltransferases / Q000378:metabolism; D011938:Rec A Recombinases / Q000378:metabolism; D013014:SOS Response, Genetics; D012697:Serine Endopeptidases; D015398:Signal Transduction; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); D014466:Ultraviolet Rays / Q000009:adverse effects*; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D002701:Chloramphenicol; D004262:DNA Restriction Enzymes; D015280:DNA Restriction-Modification Enzymes; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D008780:Methyltransferases; D011938:Rec A Recombinases; D012697:Serine Endopeptidases; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); D000099160:LexA Repressor Protein; C069326:mcrC protein, E coli; C058693:Dam methyltransferase; C499294:dam protein, E coli; C070141:Mrr protein, E coli; C089629:endodeoxyribonuclease EcoKI; C060629:endodeoxyribonuclease McrA; C059678:mcrB protein, E coli