RNase E processing of essential cell division genes mRNA in Escherichia coli.

The ratio of the FtsZ to FtsA proteins determines the correct initiation of cell division in Escherichia coli. The genes for these proteins are contiguous on the chromosome. Although both genes are transcribed from common promoters, the presence of ftsZ-specific promoters, along with differences in the efficiency of translation of their respective mRNAs, contribute to the increased relative expression of ftsZ. We report here that the polycistronic ftsA-ftsZ transcripts are cleaved by RNase E and that this cleavage affects the decay of ftsA and ftsZ mRNA. As a consequence of the cleavage, RNase E also contributes to the differential expression of the two genes.