Structural and Segregational Stability of Various Replicons inActinobacillus actinomycetemcomitans

Few vectors suitable for cloning inActinobacillus actinomycetemcomitans,a periodontal pathogen, have been described. These plasmids were based either on the nativeA. actinomycetemcomitansreplicon, pVT736-1, or derivatives of the IncP and IncQ family of plasmids. Their usefulness as cloning vectors is limited because of instability or size. Therefore, the ability of additional replicons to function inA. actinomycetemcomitanswas evaluated. Derivatives of p15A, ColE1/f1, and pWV01 transformedA. actinomycetemcomitansefficiently and exhibited no structural instability in the new host. The stable maintenance ofA. actinomycetemcomitans-specific DNA fragments inserted into the p15A derivative, pDMG4, demonstrated the ability of this plasmid to function as a cloning vector. In addition, pVT736-1 was used to clone selectable markers directly intoA. actinomycetemcomitans.These constructs were structurally and segregationally stable.