Nakamura M, Ogata K, Nagamine T, Tajima K, Matsui H, Benno Y
Rumen Microbiology Research Team, STAFF-Institute, 446-1 Ippaizuka, Kamiyokoba, Tsukuba, Ibaraki 305-0854, Japan.
Curr Microbiol. 2001 Jul;43(1):11-6. doi: 10.1007/s002840010252.
The cryptic plasmid pSBO1 (3904 bp) was isolated from Streptococcus bovis JB1. pSBO1 contained an open reading frame (ORF) that is homologous to sequences encoding the replication protein (Rep) in pEFC1 (isolated from Enterococcus faecalis), pSK639 (Staphylococcus epidermidis), pLA103 (Lactobacillus acidophilus), and pUCL287 (Tetragenococcus halophila). In addition, four 22-bp direct repeats (DRs) were located upstream of the putative replication gene (rep) of pSBO1. Recombinant plasmids (pSBE10 and pSBE11) containing the DRs and putative rep of pSBO1 replicated in S. bovis 12-U-1 and no8 strains. This result indicates that the putative rep encoded Rep and that the replicon of pSBO1 contained the DRs and the rep. Gel shift assays showed that the Rep of pSBO1 bound the 22-bp DRs.
隐秘质粒pSBO1（3904 bp）是从牛链球菌JB1中分离得到的。pSBO1含有一个开放阅读框（ORF），该阅读框与pEFC1（从粪肠球菌中分离得到）、pSK639（表皮葡萄球菌）、pLA103（嗜酸乳杆菌）和pUCL287（嗜盐四联球菌）中编码复制蛋白（Rep）的序列同源。此外，在pSBO1假定的复制基因（rep）上游发现了四个22 bp的直接重复序列（DRs）。含有pSBO1的DRs和假定rep的重组质粒（pSBE10和pSBE11）在牛链球菌12-U-1和no8菌株中能够复制。这一结果表明，假定的rep编码了Rep，并且pSBO1的复制子包含DRs和rep。凝胶迁移试验表明，pSBO1的Rep能够与22 bp的DRs结合。
