Disease relevance of gtfB

• The gtfB gene coding for glucosyltransferase-I (GTF-I) activity previously isolated from Streptococcus mutans GS-5 was insertionally inactivated with the newly constructed transposon MudE in an Escherichia coli background [1].
• Two strain GS-5 homologous tandem genes, gtfB and gtfC, coding for GTF-I and GTF-S activities respectively, were demonstrated to undergo recombination when introduced into recombination-proficient Escherichia coli transformants [2].
• GTF-I and GTF-SI were expressed from two Streptococcus milleri or Escherichia coli transformants harboring gtfB or gtfC, respectively [3].
• Streptococcus mutans produces a number of extracellular sucrose-metabolizing enzymes that contribute to the ability of the organism to cause dental caries, including three glucosyltransferases, the products of the gtfB, gtfC and gtfD genes, and a fructosyltransferase, encoded by the ftf gene [4].
• In order to confirm their molecular identity, S. mutans and Streptococcus sobrinus were submitted to the PCR method, using specific primers for portions of the glucosyltransferase genes (gtfB and gtfI, respectively) [5].

High impact information on gtfB

• The DNA fragment coding for GTF activity from one S. mutans colonization-defective mutant, SP2, was isolated and shown also to have undergone recombination between the gtfB and gtfC genes, resulting in reduced GTF activity [2].
• Apigenin (0.1 mM) significantly decreased the expression of gtfB and gtfC mRNA (P < 0.05); in contrast, it increased the expression of gtfD in S. mutans growing in the planktonic state [6].
• By using this shuttle plasmid system, modulation of gene function by inducible antisense RNA expression was demonstrated for comC antisense fragments of different sizes as well as for distinct gtfB antisense fragments [7].
• Inactivation of the gbpA gene of Streptococcus mutans increases virulence in a gnotobiotic rat model and also promotes in vivo accumulation of organisms in which gtfB and gtfC have recombined to reduce virulence (K. R. O. Hazlett, S. M. Michalek, and J. A. Banas, Infect. Immun. 66:2180-2185, 1998) [8].
• In this study we report the cloning, expression, and characterization of the catalytic (CAT) and glucan-binding (GLU) domains of S. mutans GTF-I encoded by gtfB [9].

Chemical compound and disease context of gtfB

• Recombination between gtfB and gtfC is required for survival of a dTDP-rhamnose synthesis-deficient mutant of Streptococcus mutans in the presence of sucrose [10].
• RESULTS: Our results indicate that iodine and PI in a tetraglycol carrier cause enhancement of expression of gtfB in Streptococcus mutans in biofilms but not in planktonic bacteria [11].
• We examined the effects of phosphorothioate-modified antisense oligodeoxyribonucleotides (PS-ODN) targeted to mRNA transcribed from gtfB, which encodes synthesis of water-insoluble glucans in Streptococcus mutans [12].
• The expression of Streptococcus mutans mutant glucosyltransferase-I enzymes in S. sanguis and S. milleri suggests that cell-associated glucosyltransferase activity is dependent upon both glucan synthesis and glucan binding by the carboxyl-terminal repeating units of the enzyme [13].

Biological context of gtfB

• Specifically, fusions were generated between cat and the S. mutans genes encoding fructosyltransferase (ftf) and the glucosyltransferase B/C (gtfB/C) operon [14].
• The gtfB gene was subcloned into plasmid pACYC184 into E. coli and exhibited GTF activity when carried on GS-5 inserts as small as 5 kilobases [15].
• This sequence, deduced from the nucleotide sequence of gtfB from Streptococcus mutans GS5, has been found to be strongly conserved in Gtfs from several mutans streptococci [16].
• The rates were consistent with the frequency of spontaneous gene fusions between gtfB and gtfC, suggesting that the spontaneous recombinant organisms were selected in the presence of sucrose [10].
• The gtfB gene coding for a glucosyltransferase (GTF) activity of Streptococcus mutans GS-5 was isolated on a 15.4-kilobase DNA fragment by using a lambda L47.1 gene library [15].

Associations of gtfB with chemical compounds

• Similar to gtfB, the expression of gtfC was also induced with the presence of all the tested carbohydrates except for xylitol at early growth and glucose and fructose at late exponential phase [17].
• GtfD was less influenced compared to the gtfB and gtfC, demonstrating enhanced expression especially in the presence of sorbitol, glucose, mannitol and xylitol at early exponential phase and mannitol at late exponential phase [17].
• These results indicate that the gtfB gene codes for a GTF involved in insoluble glucan synthesis in strain GS-5 [15].
• The gtfB gene was insertionally inactivated by introducing a gene fragment coding for erythromycin resistance into the GTF coding region [15].
• Melibiose-negative phenotypes (n = 10) isolated from four families showed gtfB RFLP patterns identical to each other [18].

Other interactions of gtfB

• Our findings show that dietary carbohydrates have a major influence on the transcription of ftf, gtfB, gtfC and gtfD, but less on vicR [17].
• No sequence homologies were observed between the gtfA gene or protein and the gtfI or gtfB gene and its protein [19].
• Thus, a Tetr gene was inserted adjacent to gtfB in the appropriate mapping vector and within the ftf and scrB genes with a mini-Mu transposon (Mu dT) [20].
• The gbpA mutant strain became enriched in vivo with organisms that had undergone a recombination involving the gtfB and gtfC genes [21].

Analytical, diagnostic and therapeutic context of gtfB

• Additionally, expression of the gtfB/C operon is increased in S. mutans cells bound to artificial tooth pellicles [14].
• Genetic polymorphisms in genes coding for the glucosyltransferases were detected among Streptococcus mutans serotype c strains by Southern blot analysis with DNA probes located within the gtfB gene (H. Aoki, T. Shiroza, M. Hayakawa, S. Sato, and H. K. Kuramitsu, Infect. Immun. 53:587-594, 1986) [22].
• Based on real-time PCR, Smuvic+ showed increased gtfBCD, gbpB, and ftf expression, while a recombinant VicR fusion protein was shown to bind the promoter regions of the gtfB, gtfC, and ftf genes [23].
• Sequence analysis of the gtfB gene from Streptococcus mutans [24].
• Furthermore, confocal laser scanning microscopy was carried out on biofilms attached to polystyrene plates; enhanced gtfB expression was observed in various microcolonies across these biofilms [25].

References