TY - JOUR
T1 - Putative mannose-specific phosphotransferase system component IID represses expression of suilysin in serotype 2 Streptococcus suis
AU - Lun, Shichun
AU - Willson, P. J.
N1 - Funding Information:
We thank E. Maguin for pGh9:IS S1, M. Fontaine and R. Brownlie for technical assistance, and T. Beskorwayne and P. Griebel for FACS assay. This work was supported by the Natural Science and Engineering Research Council of Canada (NSERC) and the Canadian Network for Bacterial Pathogens of Swine.
PY - 2005/2/25
Y1 - 2005/2/25
N2 - In this study, we generated a genomic mutant library from a North American strain of serotype 2 Streptococcus suis using the pGh9:ISS1 transposition vector. Suilysin is the hemolysin made by S. suis. A hyper-hemolytic mutant was identified by screening for hemolytic phenotype using media with human blood. The hyper-hemolytic phenotype was characterised by a quantitative hemolysis microplate method. The use of green fluorescent protein (GFP) as a reporter also showed that suilysin gene expression was greater in the mutant. DNA sequence analysis of 3.8 kb surrounding the ISS1 insertion site revealed four open reading frames (ORFs) with three consecutive ORFs that belong to a putative mannose-specific phosphotransferase system (PTS). The S. suis gene homologous to mannose permease IID, manN, was interrupted by the transposon. A complementation test showed that manN repressed the expression of suilysin and the absence of manN was responsible for the hyper-hemolytic phenotype. However, both wild type and isogenic hyper-hemolytic mutant S. suis fermented mannose, glucose and lactose. Thus, despite its potential roles in carbohydrate transport, phosphorylation and metabolism, the manN homologue in the putative mannose-specific PTS regulates gene expression in S. suis.
AB - In this study, we generated a genomic mutant library from a North American strain of serotype 2 Streptococcus suis using the pGh9:ISS1 transposition vector. Suilysin is the hemolysin made by S. suis. A hyper-hemolytic mutant was identified by screening for hemolytic phenotype using media with human blood. The hyper-hemolytic phenotype was characterised by a quantitative hemolysis microplate method. The use of green fluorescent protein (GFP) as a reporter also showed that suilysin gene expression was greater in the mutant. DNA sequence analysis of 3.8 kb surrounding the ISS1 insertion site revealed four open reading frames (ORFs) with three consecutive ORFs that belong to a putative mannose-specific phosphotransferase system (PTS). The S. suis gene homologous to mannose permease IID, manN, was interrupted by the transposon. A complementation test showed that manN repressed the expression of suilysin and the absence of manN was responsible for the hyper-hemolytic phenotype. However, both wild type and isogenic hyper-hemolytic mutant S. suis fermented mannose, glucose and lactose. Thus, despite its potential roles in carbohydrate transport, phosphorylation and metabolism, the manN homologue in the putative mannose-specific PTS regulates gene expression in S. suis.
KW - Gene regulation
KW - Mannose-specific phosphotransferase system
KW - Mutagenesis
KW - Streptococcus suis
KW - Suilysin
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U2 - 10.1016/j.vetmic.2004.10.017
DO - 10.1016/j.vetmic.2004.10.017
M3 - Article
C2 - 15708813
AN - SCOPUS:13644249107
SN - 0378-1135
VL - 105
SP - 169
EP - 180
JO - Veterinary Microbiology
JF - Veterinary Microbiology
IS - 3-4
ER -