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Evolution and function of the neisserial dam ‐replacing gene
Author(s) -
Cantalupo Giuseppina,
Bucci Cecilia,
Salvatore Paola,
Pagliarulo Caterina,
Roberti Vera,
Lavitola Alfredo,
Bruni Carmelo Bruno,
Alifano Pietro
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02388-2
Subject(s) - neisseria , transposable element , gene , biology , genetics , microbiology and biotechnology , phase variation , restriction enzyme , lactococcus lactis , virulence , bacteria , mutant , lactic acid
Phase variation through slippage‐like mechanisms involving homopolymeric tracts depends in part on the absence of Dam‐methylase in several pathogenic isolates of Neisseria meningitidis . In Dam‐defective strains drg ( dam ‐replacing gene), flanked by pseudo‐transposable small repeated elements (SREs), replaced dam . We demonstrate that drg encodes a restriction endonuclease ( Nme BII) that cleaves 5′‐GmeATC‐3′. drg is also present in 50% of Neisseria lactamica strains, but in most of them it is inactive because of the absence of an SRE‐providing promoter. This is associated with the presence of GATmeC, suggesting an alternative restriction‐modification system (RM) specific for 5′‐GATC‐3′, similar to Sau 3AI‐RM of Staphylococcus aureus 3A, Lactococcus lactis KR2 and Listeria monocytogenes .