Premium
Phase variable type III restriction‐modification systems of host‐adapted bacterial pathogens
Author(s) -
Fox Kate L.,
Srikhanta Yogitha N.,
Jennings Michael P.
Publication year - 2007
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2007.05873.x
Subject(s) - phase variation , biology , regulon , neisseria meningitidis , haemophilus influenzae , gene , genetics , pilus , neisseria gonorrhoeae , microbiology and biotechnology , restriction enzyme , dna , antigenic variation , neisseria , epigenetics , phenotype , gene expression , bacteria , virulence
Summary Phase variation, the high‐frequency on/off switching of gene expression, is a common feature of host‐adapted bacterial pathogens. Restriction‐modification (R‐M) systems, which are ubiquitous among bacteria, are classically assigned the role of cellular defence against invasion of foreign DNA. These enzymes are not obvious candidates for phase variable expression, a characteristic usually associated with surface‐expressed molecules subject to host immune selection. Despite this, numerous type III R‐M systems in bacterial pathogens contain repetitive DNA motifs that suggest the potential for phase variation. Several roles have been proposed for phase variable R‐M systems based on DNA restriction function. However, there is now evidence in several important human pathogens, including Haemophilus influenzae , Neisseria meningitidis and Neisseria gonorrhoeae, that these systems are ‘phasevarions’ ( phase var iable regul ons ) controlling expression of multiple genes via a novel epigenetic mechanism.