title: Evolution and function of the neisserial dam-replacing gene.
abstract: 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 (NmeBII) 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 Sau3AI-RM of Staphylococcus aureus 3A, Lactococcus lactis KR2 and Listeria monocytogenes.
authors.affiliation: Dipartimento di Biologia e Patologia Cellulare e Moleculare L Califano, Università di Napoli Federico II, Naples, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cantalupo
authors.forename: C
authors.initials: C
authors.lastname: Bucci
authors.forename: P
authors.initials: P
authors.lastname: Salvatore
authors.forename: C
authors.initials: C
authors.lastname: Pagliarulo
authors.forename: V
authors.initials: V
authors.lastname: Roberti
authors.forename: A
authors.initials: A
authors.lastname: Lavitola
authors.forename: C B
authors.initials: CB
authors.lastname: Bruni
authors.forename: P
authors.initials: P
authors.lastname: Alifano
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology*; D001483:Base Sequence; D015252:Deoxyribonucleases, Type II Site-Specific / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000201:enzymology* / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; C426903:Drg protein, Neisseria; D012333:RNA, Messenger; D015252:Deoxyribonucleases, Type II Site-Specific