Trasncript abundance alters by RhlB P238L mutation. Escherichia coli

PNPase, one of the major enzymes with 3ʹ-to-5ʹ single-stranded RNA (ssRNA) degradation and processing activities, can interact with the RNA helicase RhlB independent of RNA degradosome formation in E. coli. Here we report that loss of interaction between RhlB and PNPase impacts cysteine homeostasis in E. coli. By random mutagenesis, we identified a mutant RhlBP238L that loses 75% of its ability to interact with PNPase, but retains normal interaction with RNase E and RNA in addition to exhibiting normal helicase activity. Applying microarray analyses to an E. coli strain with impaired RNA degradosome formation, we investigated the biological consequences of a weakened interaction between RhlB and PNPase. Overall design: BL21(DE3) rne131 DrhlB expressing with pFlag-only, pFlagRhlB or pFlagRhlBP238L grown at 30°C in LB medium to an OD600 of 0.55-0.6. Biological replicates:6 for flag-only, 3 for FlagRhlB and 3 for FlagRhlBP238L independently grown and harvested.