Identification of genes associated with mutacin I production in Streptococcus mutans using random insertional mutagenesis.
Streptococcus mutans is a major pathogen implicated in dental caries. Its virulence is enhanced by its ability to produce bacteriocins, called mutacins, which inhibit the growth of other Gram-positive bacteria. The goal of this study is to use a random insertional mutagenesis approach to search for genes that are associated with mutacin I production in the virulent strain UA140. A random insertional mutagenesis library consisting of 11,000 clones was constructed and screened for a mutacin-defective phenotype. Mutacin-defective clones were isolated, and their insertion sites were determined by PCR amplification or plasmid rescue followed by sequencing. A total of twenty-five unique genes were identified. These genes can be categorized into the following functional classes: two-component sensory systems, stress responses, energy metabolism and central cellular processes. Several conserved hypothetical proteins with unknown functions were also identified. These results suggest that mutacin I production is stringently controlled by diverse and complex regulatory pathways.
Tsang
Phoebe
P
UCLA School of Dentistry, Los Angeles, CA 90025, USA.
Merritt
Justin
J
UCLA Molecular Biology Institute, Los Angeles, CA 90025, USA.
Nguyen
Trang
T
UCLA School of Dentistry, Los Angeles, CA 90025, USA.
Shi
Wenyuan
W
UCLA Molecular Biology Institute, Los Angeles, CA 90025, USA.|UCLA School of Dentistry, Los Angeles, CA 90025, USA.
Qi
Fengxia
F
UCLA School of Dentistry, Los Angeles, CA 90025, USA.
D001430:Bacteriocins / Q000235:genetics*; D005798:Genes, Bacterial / Q000502:physiology; D016254:Mutagenesis, Insertional; D013295:Streptococcus mutans / Q000235:genetics*
D001430:Bacteriocins; C416548:mutacin I