[Regulatory role of small RNA in mutacin IV expression in ].

OBJECTIVE

To analyze the role of small RNA in posttranscriptional regulation of mutacin IV expression in Streptococcus mutans.

METHODS

The potential target genes of were predicted using RNAhybrid, RNAPredator and IntaRNA. We collected 10 () strains with high expression of mutacin IV and another 10 strains that did not express mutacin IV screened by inhibition zone test, and the expression levels of and the candidate target genes in these strains were detected by qPCR. Using synthesized mimics and inhibitors of , we constructed strains with high or low expression via electroporation based on the standard strain of UA159, and analyzed the expression levels of and its candidate target genes in these strains. We also examined the binding ability of to its target gene using electrophoresis and a dual- luciferase reporter system.

RESULTS

The expression levels of the candidate target genes of including , , , and were significantly higher while the expression level of was significantly lower in clinical strains with high expression of mutacin IV than in those without mutacin IV expression ( < 0.05). Although the expression levels of the candidate target genes in strains with up- regulated or down- regulated expression did not differ significantly from those in the standard strain, the expression level of showed a trend of differential distribution, and was predicted to have a strong binding ability to action site.

CONCLUSION

may play a regulatory role in the expression of mutacin IV in , but the underlying mechanism remains to be explored.