Identification of an intragenic integration site for foreign gene expression in recombinant Streptococcus gordonii strains.

A new intragenic chromosomal integration site within the lacG gene of the lac operon has been identified in Streptococcus gordonii for use in the expression of foreign genes. Introduction of a portion of the Streptococcus pyogenes emm6 gene into the lacG locus resulted in the lactose-inducible surface expression of the S. pyogenes M6 protein. This result demonstrates the ability to modulate the in vitro or in vivo expression of a foreign gene in a S. gordonii recombinant using a biosynthetic metabolite.