[Functional analysis of VicK kinase activity in Streptococcus mutans].
OBJECTIVE
To investigate the regulatory function on physiology and virulence of VicK kinase activity in Streptococcus mutans.


METHODS
PCR ligation mutagenesis was used to construct a vicK knock-out mutant, and kinase activity abolished VicK was expressed by a streptococcal vector in this vicK null mutant. Colony morphology, overnight culture, biofilm formation and gene expression involved in biofilm formation were analyzed. Delta VicK, strains harboring a complemented wild-type vicK, and a vector without insert were used as controls.


RESULTS
Colonies of VicK(H217A) were smoother and more elevated than that of wild-type UA159 and complementary strain SMCVicK; cells from VicK(H217A) overnight culture coaggregated on the bottom of glass tubes; no obvious alteration was observed in VicK(H217A) biofilm; expressions of gbpB, ftf, gtfD were repressed while gtfB/C were up-regulated (P < 0.05).


CONCLUSIONS
VicK kinase activity is important for maintaining normal growth, biofilm formation and expression of genes involved in biofilm formation in Streptococcus mutans.
Laboratory of Oral Diseases, Department of Operative Dentistry and Endodontics, West China Stomatological Hospital, Sichuan University, Chengdu 610041, China.
Qiong
Q
Zhang
Laboratory of Oral Diseases, Department of Operative Dentistry and Endodontics, West China Stomatological Hospital, Sichuan University, Chengdu 610041, China.
Shi-Da
SD
Wang
Laboratory of Oral Diseases, Department of Operative Dentistry and Endodontics, West China Stomatological Hospital, Sichuan University, Chengdu 610041, China.
Xue-Dong
XD
Zhou
Laboratory of Oral Diseases, Department of Operative Dentistry and Endodontics, West China Stomatological Hospital, Sichuan University, Chengdu 610041, China.
Lei
L
Cheng
Laboratory of Oral Diseases, Department of Operative Dentistry and Endodontics, West China Stomatological Hospital, Sichuan University, Chengdu 610041, China.
Yu-Qing
YQ
Li
Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G1G6, Canada.
Dilani B
DB
Senadheera
Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G1G6, Canada.
Dennis G
DG
Cvitkovitch
D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D013295:Streptococcus mutans / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
D001426:Bacterial Proteins; D008565:Membrane Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase