RNA components of Escherichia coli degradosome: Evidence for rRNA decay
- *Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, ‡Institute of Biochemistry, National Yang-Ming University, Taipei 112, and §Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, 100, Taiwan, Republic of China
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Edited by Stanley N. Cohen, Stanford University School of Medicine, Stanford, CA, and approved December 31, 1997 (received for review September 19, 1997)
Abstract
Recently, we found that a multicomponent ribonucleolytic degradosome complex formed around RNase E, a key mRNA-degrading and 9S RNA-processing enzyme, contains RNA in addition to its protein components. Herein we show that the RNA found in the degradosome consists primarily of rRNA fragments that have a range of distinctive sizes. We further show that rRNA degradation is carried out in the degradosome by RNase E cleavage of A+U-rich single-stranded regions of mature 16S and 23S rRNAs. The 5S rRNA, which is known to be generated by RNase E processing of the 9S precursor, was also identified in the degradosome, but tRNAs, which are not cleaved by RNase E in vitro, were absent. Our results, which provide evidence that decay of mature rRNAs occurs in growing Escherichia coli cells in the RNA degradosome, implicate RNase E in degradosome-mediated decay.
Footnotes
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↵† Present address: Institute of Microbiology and Genetics, University of Vienna, A-1030 Wien, Dr. Bohr-Gasse 9, Austria.
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↵¶ To whom reprint requests should be addressed. e-mail: mbsue{at}ccvax.sinica.edu.tw.
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This paper was submitted directly (Track II) to the Proceedings Office.
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Abbreviation: PNPase, polynucleotide phosphorylase.
- Received September 19, 1997.
- Copyright © 1998, The National Academy of Sciences
