Characterization of a rolling-circle replication plasmid pLR1 from Lactobacillus plantarum LR1.
A cryptic plasmid from Lactobacillus plantarum LR1, designated pLR1, was sequenced and characterized. It consisted of a 2066-bp circular molecule with a G + C content of 52.7%. The plasmid pLR1 was predicted to contain five putative ORFs, in which ORF1 shared 93% and 92% identity with Rep proteins of pLP1 and pC30il, members of rolling-circle replication (RCR) pC194 family. Detection of single-stranded DNA (ssDNA) intermediates by Southern hybridization and mung bean nuclease treatment confirmed that pLR1 replicated via the RCR mechanism. Accumulation of ssDNA in rifampicin-treated strains implied that the host-coded RNA polymerase was involved in the conversion of ssDNA to double-stranded DNA (dsDNA). Furthermore, the copy number of pLR1 was estimated to be 36 in each cell by real-time polymerase chain reaction.
College of Food Science and Nutritional Engineering, China.
Ruoyu
R
Li
Zhengyuan
Z
Zhai
Sheng
S
Yin
Ying
Y
Huang
Qing
Q
Wang
Yunbo
Y
Luo
Yanling
Y
Hao
D001483:Base Sequence; D004261:DNA Replication; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004277:DNA, Single-Stranded / Q000032:analysis / Q000235:genetics; D018628:Gene Dosage; D048191:Lactiplantibacillus plantarum / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000032:analysis / Q000235:genetics*; D018741:Replication Origin
D004269:DNA, Bacterial; D004277:DNA, Single-Stranded