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Updated: Feb 15, 2026

Generation of a Gene-disrupted Streptococcus mutans Strain Without Gene Cloning
Published on: October 23, 2017
A novel plasmid, pSAA0430-08, from Streptococcus anginosus subsp. anginosus strain 0430-08
Atsushi Tabata1, Douglas Deutsch2, Seiya Otsuka3
1Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan.
Abstract:
Mobile genetic elements (MGEs) are the genetic material often involved in the interspecies and intraspecies genetic transduction in bacteria. However, little is known about MGEs in the Anginosus group of streptococci (AGS), one of the streptococcal groups found in the oral cavity of humans. We looked for the presence of MGEs in Streptococcus anginosus subsp. anginosus (SAA), a representative species belonging to AGS, and found a novel plasmid from SAA strain 0430-08. This plasmid was 7038bp and ~31% G/C content which we named pSAA0430-08, and examined its genetic structure and characteristics. Open reading frame (ORF) prediction revealed that pSAA0430-08 was composed of 10 ORFs including a putative plasmid replication protein (ORF1) and a putative toxin-antitoxin system (ORF9 and ORF10). Between ORF10 and ORF 1, four tandem repeats of 22bp each, generally termed as iteron, were also observed. Using variant plasmids of pSAA0430-08, we confirmed that both ORF1 and iteron were necessary for replication in host cells. Interestingly, the region from ORF4 to ORF7 showed homology with a genomic DNA segment of S. gordonii strains. Thus, this plasmid may travel between the different species in Streptococci, i.e., S. gordonii and S. anginosus.
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