Pneumococcal MarR family protein SPD_0379 regulating the expression of gene rafX and the biosynthesis of teichoic acids

Abstract:

Objective：To determine the regulative effect of Streptococcus pneumoniae MarR family protein SPD_0379 on the biosyn－thesis ofteichoic acid. Methods：EMSA was employed to analyze whether protein SPD_0379 bound to rafX gene promoter sequence. The change of bacterial rafX gene expression was observed by LacZ reporter gene. Dot blot，ELISA techniques and flow cytometry analysis were implemented to reveal the change of the concentration of teichoic acid. Results：A specific binding between proteins SPD_0379 and rafX gene promoter sequence was observed. After spd_0379 gene deficiency，the expressions of bacterial rafX gene were up-regulated（t=10.010，P=0.001），with the concentration of teichoic acid significantly up-regulated in D39Δspd_0379 detected by both dot blotting and ELISA（t=5.848，P=0.004；t=4.653，P=0.001），and the autolysis of spd_0379 deficient strains were signifi－cantly earlier than wide type D39. Conclusion：Protein SPD_0379 regulates the expression of rafX gene，inhibits the synthesis of bacterial teichoic acid，and is involved in the regulation of bacterial autolysis.