%0 Journal Article %A Nobbs, Angela H. %A Vajna, Reka M. %A Johnson, Jeremy R. %A Zhang, Yongshu %A Erlandsen, Stanley L. %A Oli, Monika W. %A Kreth, Jens %A Brady, L. Jeannine %A Herzberg, Mark C. %T Consequences of a sortase A mutation in Streptococcus gordonii %D 2007 %J Microbiology, %V 153 %N 12 %P 4088-4097 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.2007/007252-0 %K wtV288, S. gordonii V288 wild-type %K P1, antigen class I/II surface protein of Streptococcus mutans %K DL1srtA+, complemented DL1srtA− %K V288srtA−, sortase A negative mutant in S. gordonii V288 wild-type %K DL1srtA−, sortase A negative mutant in Streptococcus gordonii DL1 wild-type %K wtDL1, S. gordonii DL1 wild-type %K RU, resonance units %I Microbiology Society, %X Sortase A (SrtA) is required for cell-wall anchoring of LPXTG-containing Gram-positive surface proteins. It was hypothesized, therefore, that disruption of the srtA gene would alter surface anchoring and functions of target LPXTG motif-bearing SspA and SspB proteins of Streptococcus gordonii. Mutant strains in srtA (V288srtA −, DL1srtA− ) were constructed in S. gordonii V288 (wtV288) and DL1 (wtDL1). When compared to wtV288, the V288srtA− mutant showed decreased biofilm formation on polystyrene, and reduced binding to immobilized purified salivary agglutinin (BIAcore analysis). The wtV288 and V288srtA− strains were similar in ultrastructure, but immunogold-labelled SspA/SspB surface expression was reduced on the V288srtA− mutant. DL1srtA− was also complemented to obtain DL1srtA+ . From the wild-type strains (wtV288, wtDL1), srtA− mutants (V288srtA− , DL1srtA− ), and the complemented mutant (DL1srtA+ ), cytoplasmic, cell-wall and released extracellular protein fractions were isolated. Each fraction was analysed by SDS-PAGE and immunoblotting with anti-P1. Spent medium from srtA− mutant cells contained over-represented proteins, including SspA/SspB (P1 antigen). Mutants showed less P1 on the cell surface than wild-types, as estimated using whole-cell ELISA, and no P1 appeared in the cytoplasmic fractions. Expression of several adhesin genes (sspA/B, cshA/B, fbpA) was generally upregulated in the mutants (V288srtA− , DL1srtA− ), but restored to wild-type levels in DL1srtA+ . These data therefore imply that in addition to its role in processing LPXTG-containing adhesins, sortase A has the novel function of contributing to transcriptional regulation of adhesin gene expression. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.2007/007252-0