Distribution and sequencing of enterobacterial repetitive intergenic consensus sequence elements in Streptococcus mutans serotype c

Objective: The banding pattern of Streptococcus mutans strains generated using repetitive extragenic palindromic PCR (rep-PCR) with enterobacterial repetitive intergenic consensus (ERIC) primers has been shown previously. In the present study, the sequencing and analysis of gene sequences of the 6 most intense and commonly occurring amplicons from S. mutans serotype c was investigated. Methods: The sequences of the amplicons from S. mutans serotype c strain by using rep-PCR with ERIC1R and ERIC2 primers were compared to the whole genome sequence of S. mutans UA159 and NN2025 strains. Results: The amplicons were found to contain partial gene sequences coding for proteins such as the hypothetical protein, glucan binding protein A, putative methylated-DNA-protein- cysteine S-methyl-transferase, putative D-3-phosphoglycerate dehydrogenase, putative excinuclease ABC (subunit A) and putative GTP-binding protein. The locations of 5 of the 6 amplicons were found to be assembled downstream in the UA159 genome. The coding direction of the amplicons in the NN2025 genome was in reverse orientation relative to that in the UA159 strain, except in the 2170-bp amplicon. Conclusions: The repeating sequence elements of ERIC in S. mutans serotype c are located on one side of the genome and have less frequency and similarity compared to those in enterobacteria.