Nucleotide Sequencing and Transcriptional Analysis of Two Tandem Genes Encoding Glucosyltransferase (Water‐Soluble‐Glucan Synthetase) in Streptococcus cricetus HS‐6

Abstract

Two tandem genes encoding glucosyltransferase synthesizing water-soluble glucan (GTF-S) were cloned from the lambda gene library of Streptococcus cricetus HS-6 (serotype a) using anti-GTF-S antibody, and the nucleotide sequences were analyzed. The two genes (ORF1 and ORF2) were identified as streptococcal glucosyltransferases based on the following evidence: [1] the deduced amino acid sequences of their products have an active site for catalytic action and C-terminal repeated units for dextran binding, and [2] a homology search revealed that the ORF1 and ORF2 products are homologous to the GtfS protein (77.4%) of S. downei Mfe28 and Gt1T protein (83.8 %) of S. sobrinus OMZ176, respectively, which are both known to have GTF-S activity. Therefore, ORF1 and ORF2 might be designated gtfS and gtfT of S. cricetus, respectively. A Northern blotting and RNase protection assay suggested that the gtfS and gtfl of S. cricetus are transcribed as a single bicistronic mRNA as well as separate monocistronic mRNAs. Primer extension analysis indicated multiple transcriptional start points for each gene.

Sequence and phylogenetic analyses of novel glucosyltransferase genes of mutans streptococci isolated from pig oral cavity

“…The prepared protein sample of S. criceti was only recognized with the ant-GTF-T MAb (data not shown). This result coincides with the previous study showing that S. criceti has gtfS and gtfT genes (Inoue et al, 2000). Protein from S. orisuis was not detected by anti-GTF-U and anti-GTF-T MAbs (data not shown).…”

Fermentable-sugar-level-dependent regulation of leukotoxin synthesis in a variably toxic strain of Actinobacillus actinomycetemcomitans The GenBank/EMBL/DDBJ accession number for the sequence data in this paper is AB054839.

“…Total cellular RNA was prepared from 20 ml culture sampled from the chemostat by the hot phenol extraction method of Emory & Belasco (1990). Northern blot analysis was performed basically according to the protocol described by Inoue et al (2000). Briefly, RNA samples were electrophoresed on 1 % (w\v) agarose gels containing 6n7% (v\v) formaldehyde and transferred onto nylon filters (Hybond-N membrane ; Amersham) by capillary blotting.…”

Sequence and phylogenetic analyses of the water‐soluble glucan synthesizing‐glucosyltransferase genes of Streptococcus dentirousetti

“…WIG‐ and WSG‐synthesizing GTF enzymes interact with each other to facilitate production of adhesive WIGs, which facilitate colonization of tooth surfaces by oral bacteria . The presence in S. criceti HS6 of tandemly aligned WSG‐synthesizing GTF genes, designated gtfS and gtfT , has been confirmed and PCR sequencing suggested there could be a portion of gtfT in S. dentirousetti . The purpose of this study was to determine the WSG‐synthesizing GTF gene sequences in S. dentirousetti and to elucidate the antigenic properties of this organism's WSG‐synthesizing GTF gene products.…”

“…orisuis NUM1001, S. criceti HS6, and S. dentirousetti NUM1303, isolated from pig, hamster and fruit bat, respectively, have been analyzed and these GTF genes found to belong to the S. sobrinus gtfI homolog. WSGs, produced by WSG‐synthesizing GTF enzymes whose products differ in both molecular weight and the degree of branching of their glucosyl residues, are also important because they are essential for the primer‐dependent WIG‐synthesizing GTFs that start WIG synthesis . It is known that S. mutans possess a WSG‐synthesizing GTF, GTF‐D, and that S. sobrinus possess three types of WSG‐synthesizing GTFs, GTF‐S, ‐T, and ‐U, which are encoded by gtfD , gtfS , gtfT , and gtfU , respectively .…”