The replicon of the cryptic plasmid pSBO1 isolated from Streptococcus bovis JB1

The cryptic plasmid pSBO1 (3904 bp) was isolated from Streptococcus bovis J B1. pSBO1 contained an open reading frame (ORF) that is homologous to seque nces encoding the replication protein (Rep) in pEFC1 (isolated from Enteroc occus faecalis), pSK639 (Staphylococcus epidermidis), pLA103 (Lactobacillus acidophilus), and pUCL287 (Tetragenococcus halophila). In addition, four 2 2-bp direct repeats (DRs) were located upstream of the putative replication gene (rep) of pSBO1. Recombinant plasmids (pSBE10 and pSBE11) containing t he DRs and putative rep of pSBO1 replicated in S. bovis 12-U-1 and no8 stra ins. This result indicates that the putative rep encoded Rep and that the r eplicon of pSBO1 contained the DRs and the rep. Gel shift assays showed tha t the Rep of pSBO1 bound the 22-bp DRs.