Dual-level autoregulation of theE. coliDeaD RNA helicase via mRNA stability and Rho-dependent transcription termination

Abstract

ABSTRACTDEAD-box proteins (DBPs) are RNA remodeling factors associated with RNA helicase activity that are found in nearly all organisms. Despite extensive studies on the mechanisms used by DBPs to regulate RNA function, very little is known about how DBPs themselves are regulated. In this work, we have analyzed the expression and regulation of DeaD/CsdA, the largest of the DBPs inEscherichia coli(E. coli). We show thatdeaDtranscription initiates 838 nts upstream of the start of the coding region. We have also found that DeaD is autoregulated through a negative feedback mechanism that operates both at the level of mRNA stability and Rho-dependent transcription termination, and this regulation is dependent upon the 5’ untranslated region (5’ UTR). These findings suggest that DeaD might be regulating the conformation of its own mRNA through its RNA helicase activity to facilitate ribonuclease and Rho access to its 5’UTR.