The essential two-component regulatory system encoded by yycF and yycG modulates expression of the ftsAZ operon in Bacillus subtilis

Essential two-component systems are now being identified in bacteria. The B acillus subtilis yycF gene encoding a response regulator, and its orthologu e in Staphylococcus aureus, were reported recently to be essential for cell growth, although genes under their control have yet to be identified. The essential nature of the yycF regulator gene and its cognate kinase gene, yy cG, in B. subtilis was also noted during the course of construction of a kn ockout mutant bank of newly identified genes in the genome sequence project . It was found that yycG could be deleted in the presence of an active form of the YycF protein, thereby suggesting direct interaction between YycG an d YycF. Production of mini-cells and reduction in cell length occurred when the YycF regulator was overproduced in B. subtilis. These observations led to the finding that YycF overproduction up-regulated the expression from t he P1 promoter of the cell division operon, ftsAZ. In addition, the YycF pr otein binds to the Pt promoter region in vitro. These results clearly indic ate that the essential two-component regulatory system encoded by yycF and yycG genes has the potential to modulate expression of the ftsAZ operon in B. subtilis.