title: Identification of a divergent M protein gene and an M protein-related gene family in Streptococcus pyogenes serotype 49.
abstract: The antigenically variant M protein of Streptococcus pyogenes enhances virulence by promoting resistance to phagocytosis. The serum opacity factor (OF), produced by a subset of M serotypes, is also antigenically variant, and its antigenic variability exactly parallels that of M protein. OF-positive and OF-negative streptococci are also phenotypically distinguishable by a number of other criteria. In order to study the differences between OF-positive and OF-negative streptococci, we cloned and sequenced the type 49 M protein gene (emm49), the first to be cloned from an OF-positive strain. This gene showed evolutionary divergence from the OF-negative M protein genes studied previously. Furthermore, emm49 was part of a gene family, in contrast to the single-copy nature of previously characterized M protein genes.
authors.affiliation: Department of Microbiology, University of Minnesota, Minneapolis 55455.
authors.forename: E J
authors.initials: EJ
authors.lastname: Haanes
authors.forename: P P
authors.initials: PP
authors.lastname: Cleary
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins; D003001:Cloning, Molecular; D015870:Gene Expression; D005798:Genes, Bacterial; D014644:Genetic Variation; D007256:Information Systems; D008969:Molecular Sequence Data; D005810:Multigene Family; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D012703:Serotyping; D012984:Software; D013297:Streptococcus pyogenes / Q000145:classification / Q000235:genetics*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein