Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9133957 | Plasmid | 2005 | 12 Pages |
Abstract
This work describes a novel rolling-circle replicating (RCR) plasmid pBMBt1 from Bacillus thuringiensis subsp. darmstadiensis (INTA Mo14-4) encoding an insecticidal crystal protein-like gene. pBMBt1 (6700Â bp) contains three ORFs and their putative transcription initiation sites and Shine-Dalgarno sequences were localized. ORF1 encodes a 34.6Â kDa protein which showed identity with the protein CryC53 from B. thuringiensis subsp. cameroun (24.6%), the Cry15Aa insecticidal crystal protein from B. thuringiensis subsp. thompsoni (21.9%) and the Mtx3 protein from Bacillus sphaericus (27.8%). The ORF2 (52.3Â kDa) showed a 74% identity with the Mob protein coded by pUIBI-1 from B. thuringiensis subsp. entomocidus and 64% identity with the Mob protein of pBMY1 from Bacillus mycoides; both Mob proteins belong to the pMV158 superfamily. To evaluate the Mob protein, the plasmid pHTMob14-4 was constructed. This plasmid shows transfer frequencies of 9.1Â ÃÂ 10â6 in B. thuringiensis subsp. israelensis (4Q7GmR). The ORF3 (23.6Â kDa) gene product is homologous to the Rep protein from the plasmid pBMYdx of B. mycoides (37.6%). A putative double-strand origin with significant homology to that of B. thuringiensis plasmids, and an ssoA-type single-strand origin were also identified. Detection of single-stranded pBMBt1 DNA replicating intermediaries suggests that replication occurs via the rolling-circle mechanism.
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Authors
Pedro D. Loeza-Lara, Graciela Benintende, Jorge Cozzi, Alejandra Ochoa-Zarzosa, Victor M. Baizabal-Aguirre, Juan J. Valdez-Alarcón, Joel E. López-Meza,