Analysis of mRNA decay and rRNA processing in Escherichia coli in the absence of RNase E-based degradosome assembly

We demonstrate here that the assembly of the RNase E-based degradosome of Escherichia coli is not required for normal mRNA decay in vivo. In contrast, deletion of the arginine-rich RNA binding site (ARRBS) from the RNase E protein slightly impairs mRNA decay. When both the degradosome scaffold region and the ARRBS are missing, mRNA decay is dramatically slowed, but 9S rRNA processing is almost normal. An extensive RNase E truncation mutation (rne Delta 610) had a more pronounced mRNA decay defect at 37 degreesC than the temperature-sensitive me-1 allele at 44 degreesC. Taken together, these data suggest that the inviability associated with inactivation of RNase E is not related to defects in either mRNA decay or rRNA processing.