TY - JOUR
T1 - Analysis of the virulence of Streptococcus mutans serotype c gtfA mutants in the rat model system
AU - Barletta, R. G.
AU - Michalek, S. M.
AU - Curtiss, R.
PY - 1988
Y1 - 1988
N2 - The Streptococcus mutans serotype c gtfA gene encodes a 55-kilodalton protein which catalyzes the synthesis of a small glucan (1.5 kilodaltons) from sucrose (J.P. Robeson, R.G. Barletta, and R. Curtiss III, J. Bacteriol. 153:211-221, 1983). To investigate the role of the GftA enzyme in virulence, we constructed S. mutans gtfA mutans from three cariogenic serotype c strains. A plasmid that carried an erythromycin resistance determinant and an internal fragments of the gtfA gene but that was unable to replicate in streptococci was used to transform S. mutans. The erythromycin-resistant transformants carried a partial duplication of the internal gtfA fragments, because of the integration of plasmid sequences within the S. mutans gtfA gene, which also resulted in the inactivation of the gtfA gene. This was verified by Southern DNA hybridization analysis and Western blot studies of cellular protein extracts of the mutant strains with gtfA antiserum. Mutants were fully virulent in both germfree and conventional rats. These results do not rule out the involvement of the GtfA protein in virulence. Pucci and Macrina (M.J. Pucci and F.L. Macrina, Infect. Immun. 54:77-84, 1986) have suggested that the GtfA enzyme synthesizes a primer for water-insoluble glucans. Another S. mutants protein, presumably a glucosyltransferase, may have a similar function and, thus, may obscure the relevance of the GtfA enzyme in pathogenesis.
AB - The Streptococcus mutans serotype c gtfA gene encodes a 55-kilodalton protein which catalyzes the synthesis of a small glucan (1.5 kilodaltons) from sucrose (J.P. Robeson, R.G. Barletta, and R. Curtiss III, J. Bacteriol. 153:211-221, 1983). To investigate the role of the GftA enzyme in virulence, we constructed S. mutans gtfA mutans from three cariogenic serotype c strains. A plasmid that carried an erythromycin resistance determinant and an internal fragments of the gtfA gene but that was unable to replicate in streptococci was used to transform S. mutans. The erythromycin-resistant transformants carried a partial duplication of the internal gtfA fragments, because of the integration of plasmid sequences within the S. mutans gtfA gene, which also resulted in the inactivation of the gtfA gene. This was verified by Southern DNA hybridization analysis and Western blot studies of cellular protein extracts of the mutant strains with gtfA antiserum. Mutants were fully virulent in both germfree and conventional rats. These results do not rule out the involvement of the GtfA protein in virulence. Pucci and Macrina (M.J. Pucci and F.L. Macrina, Infect. Immun. 54:77-84, 1986) have suggested that the GtfA enzyme synthesizes a primer for water-insoluble glucans. Another S. mutants protein, presumably a glucosyltransferase, may have a similar function and, thus, may obscure the relevance of the GtfA enzyme in pathogenesis.
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M3 - Article
C2 - 2962943
AN - SCOPUS:0023852815
VL - 56
SP - 322
EP - 330
JO - Infection and Immunity
JF - Infection and Immunity
SN - 0019-9567
IS - 2
ER -