title: Prevalence of clustered regulatory interspaced short palindromic repeat (CRISPR)-like sequences in mitis-group streptococci.
abstract: Clustered regulatory interspaced short palindromic repeats (CRISPRs) have been discovered in many bacteria and archaea. Many CRISPR-like sequences have been identified in an increasing number of studies on the function of CRISPRs. One CRISPR-like sequence of approximately 240 base pairs has been found to be highly conserved within 11 genome sequences of Streptococcus pneumoniae. A specific CRISPR-like polymerase chain reaction (PCR) assay was designed with the novel primers CRISPR 5F (forward primer) 5'-CTA ATY TCA TAA CCA TAR GAA TC-3' and CRISPR 3R (reverse primer) 5'-GAT AAR ATC CTY TAA WCT TCT AG-3' to detect the presence of this CRISPR-like sequence in pneumococci, as well as in viridans-group streptococci (VGS). This study investigates the prevalence of this CRISPR-like sequence in S. pneumoniae and 12 viridans-group streptococcal species and shows its existence to be shared by the majority of S. pneumoniae and, to a lesser extent, S. mitis. This CRISPR-like sequence was also found in S. australis and it is highly conserved among these strains, suggesting possible biological functional differences from true CRISPR because this CRISPR-like sequence has relatively few repeat numbers, and adjacent homology of CRISPR-associated (cas) genes was absent. The sharing of this CRISPR-like sequence between pneumococci, the mitis group and other VGS, as well as its high sequence homology, may suggest close evolutionary emergence of this sequence between these species.
authors.affiliation: Northern Ireland Public Health Laboratory, Department of Bacteriology, Belfast City Hospital, Belfast, Northern Ireland, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Maeda
authors.forename: C E
authors.initials: CE
authors.lastname: Goldsmith
authors.forename: W A
authors.initials: WA
authors.lastname: Coulter
authors.forename: C
authors.initials: C
authors.lastname: Mason
authors.forename: J S G
authors.initials: JS
authors.lastname: Dooley
authors.forename: C J
authors.initials: CJ
authors.lastname: Lowery
authors.forename: W J
authors.initials: WJ
authors.lastname: Snelling
authors.forename: J E
authors.initials: JE
authors.lastname: Moore
mesh_terms: D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics*; D006801:Humans; D055029:Inverted Repeat Sequences / Q000235:genetics*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013045:Species Specificity; D034361:Streptococcus mitis / Q000235:genetics*; D013296:Streptococcus pneumoniae / Q000235:genetics
chemical_list: D004269:DNA, Bacterial