Relationship of M protein genes in group A streptococci.
The M protein of group A streptococci is considered one of the primary virulence determinants of this organism because it prevents phagocytosis. All of the 56 different M protein types of group A streptococci tested contain a DNA region that hybridizes with a labeled probe consisting of DNA encoding the type 6 M protein (emm6 gene). In addition, 2 of 3 functionally M- group A strains (strains that are successfully phagocytized) also contain this gene, but this DNA is not present in 1 M- strain. Of the other streptococcal groups, only groups C and G, which are closely related to group A, contain DNA that hybridizes with emm6. None of the non-streptococcal Gram-positive bacteria tested contains emm6-related DNA. In the strain from which emm6 was cloned, there appears to be only a single copy of this gene.
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology; D002352:Carrier Proteins; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D005784:Gene Amplification; D005798:Genes, Bacterial; D009693:Nucleic Acid Hybridization; D013045:Species Specificity; D013297:Streptococcus pyogenes / Q000235:genetics* / Q000276:immunology
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; C014689:streptococcal M protein