title: Molecular characterization of the lactococcal plasmid pCIS3: natural stacking of specificity subunits of a type I restriction/modification system in a single lactococcal strain.
abstract: A 6.1 kb plasmid from the Lactococcus lactis subsp. cremoris strain UC509.9, named pCIS3, was found to mediate a restriction/modification (R/M) phenotype. Nucleotide sequence analysis of pCIS3 revealed the presence of an hsdS gene, typical of type I R/M systems. The presence of this plasmid resulted in a 10(4)-fold reduction in the efficiency of plating (e.o.p.) of unmodified phage. In addition to the hsdS gene of pCIS3, two more hsdS genes were identified in strain UC509.9, one located on the chromosome downstream of a gene highly homologous to hsdM genes and a third on the smallest (4 kb) plasmid, named pCIS1. The replication region of pCIS3 was highly similar to that of a large family of lactococcal theta replicons. In addition, pCIS3 was found to encode a member of the CorA family of magnesium transporters.
authors.affiliation: National Food Biotechnology Centre1,Department of Microbiology2, and Department of Food Science and Technology3, University College Cork, Cork, Ireland.
authors.forename: Jos F M L
authors.initials: JFML
authors.lastname: Seegers
authors.affiliation: National Food Biotechnology Centre1,Department of Microbiology2, and Department of Food Science and Technology3, University College Cork, Cork, Ireland.
authors.forename: Douwe
authors.initials: D
authors.lastname: van Sinderen
authors.affiliation: National Food Biotechnology Centre1,Department of Microbiology2, and Department of Food Science and Technology3, University College Cork, Cork, Ireland.
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Fitzgerald
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001435:Bacteriophages / Q000502:physiology; D001483:Base Sequence; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins; D003035:Cobalt / Q000494:pharmacology; D003470:Culture Media; D015280:DNA Restriction-Modification Enzymes / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004352:Drug Resistance, Microbial; D013294:Lactococcus lactis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000821:virology; D008274:Magnesium / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D011995:Recombination, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D027682:Cation Transport Proteins; C072716:CorA protein, Salmonella; D003470:Culture Media; D015280:DNA Restriction-Modification Enzymes; C113046:HSDS protein, Bacteria; D003035:Cobalt; C109829:HsdM protein, Bacteria; D008274:Magnesium