Studies on Prevotella nuclease using a system for the controlled expression of cloned genes in P. bryantii TC1-1.

Available tools for genetic analysis in the anaerobic rumen bacterium Prevotella bryantii are limited to only two known systems for gene delivery, and no genes, with the exception of plasmid maintenance and selection genes, have been successfully expressed from plasmids in any species of the genus Prevotella until now. It is shown here that nucB, a newly cloned nuclease gene from P. bryantii, can be controllably expressed from shuttle vector pRH3 in P. bryantii strain TC1-1, depending on the tetracycline concentration in the growth medium. nucB expression is also growth-medium dependent and this regulation presumably takes place at the translational level. His-tagged NucB was purified from P. bryantii TC1-1 culture supernatant and was shown to degrade DNA as well as RNA; it is most likely a minor 36 kDa P. bryantii non-specific nuclease.