title: Natural genetic transformation in Streptococcus gordonii: comX imparts spontaneous competence on strain wicky.
abstract: Streptococcus gordonii Wicky becomes competent only after stimulation with conditioned medium from strain Challis as a source of competence factor (CF). A 3.2-kbp genomic fragment from Challis was found to impart spontaneous competence on Wicky by a complementation assay. Wicky clones containing the fragment secreted a heat-sensitive activity that induced competence in Wicky and in a comA insertion mutant of Challis. Activity was localized to a putative open reading frame, comX, with the potential to encode a 52-amino-acid peptide. comX had no similarity to known sequences, and a comX::ermAM insertion mutant of Challis transformed normally and secreted CF. These data suggest that a CF-independent pathway for competence induction exists in S. gordonii.
authors.affiliation: Laboratory of Microbial Ecology, National Institute of Dental Research, Bethesda, Maryland, USA. Lunsford@yoda.nidr.nih.gov
authors.forename: R D
authors.initials: RD
authors.lastname: Lunsford
authors.forename: J
authors.initials: J
authors.lastname: London
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D017077:Culture Media, Conditioned; D005816:Genetic Complementation Test; D015698:Genomic Library; D008969:Molecular Sequence Data; D010641:Phenotype; D011506:Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013291:Streptococcus / Q000145:classification / Q000235:genetics*; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; C087040:ComX protein, Bacillus subtilis; D017077:Culture Media, Conditioned; D011506:Proteins; C423628:competence factor, Streptococcus