Research Support, Non-U.S. Gov't
- Cloning and Molecular Characterization of a Novel Rolling-Circle Replicating Plasmid, pK1S-1, from Bacillus thuringiensis subsp. kurstaki K1
-
Ming Shun Li , Jong Yul Roh , Xueying Tao , Zi Niu Yu , Zi Duo Liu , Qin Liu , Hong Guang Xu , Hee Jin Shim , Yang-Su Kim , Yong Wang , Jae Young Choi , Yeon Ho Je
-
J. Microbiol. 2009;47(4):466-472. Published online September 9, 2009
-
DOI: https://doi.org/10.1007/s12275-009-0020-2
-
-
43
View
-
0
Download
-
4
Scopus
-
Abstract
-
Bacillus thuringiensis, an entomopathogenic bacterium belonging to the B. cereus group, harbors numerous extra-chromosomal DNA molecules whose sizes range from 2 to 250 kb. In this study, we used a plasmid capture system (PCS) to clone three small plasmids from B. thuringiensis subsp. kurstaki K1 which were not found in B. thuringiensis subsp. kurstaki HD-1, and determined the complete nucleotide sequence of plasmid pK1S-1 (5.5 kb). Of the six putative open reading frames (ORF2-ORF7) in pK1S-1, ORF2 (MobK1) showed approximately 90% aa identity with the Mob-proteins of pGI2 and pTX14-2, which are rolling circle replicating group VII (RCR group VII) plasmids from B. thuringiensis. In addition, a putative origin of transfer (oriT) showed 95.8% identity with those of pGI2 and pTX14-2. ORF3 (RepK1) showed relatively low aa identity (17.8~25.2%) with the Rep protein coded by RCR plasmids, however. The putative double- strand origin of replication (dso) and single-strand origin of replication (sso) of pK1S-1 exhibited approximately 70% and 64% identities with those of pGI2 and pTX14-2. ORF6 and 7 showed greater than 50% similarities with alkaline serine protease, which belongs to the subtilase family. The other 2 ORFs were identified as hypothetical proteins. To determine the replicon of pK1S-1, seven subclones were contructed in the B. thuringiensis ori-negative pHT1K vector and were electroporated into a plasmid cured B. thuringiensis strain. The 1.6 kb region that included the putative ORF3 (Rep1K), dso and ORF4, exhibited replication ability. These findings identified pK1S-1 as a new RCR group VII plasmid, and determined its replication region.