Transfer RNA Precursors Are Accumulated in Escherichia coli in the Absence of RNase E

Abstract

A temperature-sensitive E. coli mutant, which contains a heat-labile RNase E, fails to produce 5 S rRNA at a non-permissive temperature. It accumulates a number of RNA molecules in the 4-12 S range. One of these molecules, a 9S RNA, is a precursor to 5S RNA. These molecules were purified and processed in a cell-free system. Some of these RNA molecules, after processing, give rise to products the size of tRNA but not to 5S rRNA. Further characterization of the processed products of 1 precursor molecule shows that it contains tRNA1Leu and tRNA1His. RNase E is necessary but not sufficient for the processing of this molecule to mature tRNA in vitro. The accumulation of such tRNA precursors in an RNase E mutant cell and the obligatory participation of RNase E in its processing indicate that RNase E functions in the maturation of tRNA and of 5S rRNA.