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J. Bacteriol., Sep 1995, 5028-5034, Vol 177, No. 17
ND Buckley, LN Lee and DJ LeBlanc
The virulence factors of the cariogenic bacterium Streptococcus sobrinus
have been difficult to assess because of a lack of tools for the genetic
manipulation of this organism. The construction of an Escherichia
coli-Streptococcus shuttle vector, pDL289, that can be mobilized into S.
sobrinus by the conjugative plasmid pAM beta 1 was described in a previous
report. The vector contains pVA380-1 for replication and mobilization in
streptococci, the pSC101 replicon for maintenance in E. coli, a kanamycin
resistance marker that functions in both hosts, and the multiple cloning
site and lacZ from pGEM7Zf(-). pDL289 is stable with or without selection
in several species of Streptococcus. In this study, a derivative with a
deletion in the minus origin of the pVA380-1 component of pDL289 was
constructed. This derivative, pDL289 delta 202, was less stable than pDL289
in Streptococcus gordonii Challis, Streptococcus mutans, and S. sobrinus.
Both pDL289 and pDL289 delta 202 were mobilizable by pAM beta 1 into S.
sobrinus, with frequencies of 3 x 10(-6) and 1 x 10(-7) transconjugants per
recipient CFU, respectively. The cloned scrA gene of S. sobrinus 6715-10
coding for the EIISuc of the sucrose-specific phosphoenolpyruvate
phosphotransferase system was interrupted by the insertion of a
streptococcal spectinomycin resistance gene active in E. coli and
streptococci. The interrupted scrA gene was subcloned into both pDL289 and
pDL289 delta 202. Each recombinant plasmid was introduced into the DL1
strain of S. gordonii Challis, which was then used as a recipient for the
conjugative transfer of pAM beta 1.(ABSTRACT TRUNCATED AT 250 WORDS)
Copyright © 1995, American Society for Microbiology
Use of a novel mobilizable vector to inactivate the scrA gene of Streptococcus sobrinus by allelic replacement
University of Texas Health Science Center at San Antonio 78284-7758, USA.
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