Journal Article

RNA Degradosomes Exist in vivo in Escherichia coli as Multicomponent Complexes Associated with the Cytoplasmic Membrane via the N-Terminal Region of Ribonuclease E

Liou, Gunn-Guang, Cohen, Stanley N., Jane, Wann-Neng, Lin-Chao, Sue, Lin, Na-Sheng

2001

Overview

RNase E isolated from Escherichia coli is contained in a multicomponent \"degradosome\" complex with other proteins implicated in RNA decay. Earlier work has shown that the C-terminal region of RNase E is a scaffold for the binding of degradosome components and has identified specific RNase E segments necessary for its interaction with polynucleotide phosphorylase (PNPase), RhlB RNA helicase, and enolase. Here, we report electron microscopy studies that use immunogold labeling and freeze-fracture methods to show that degradosomes exist in vivo in E. coli as multicomponent structures that associate with the cytoplasmic membrane via the N-terminal region of RNase E. Whereas PNPase and enolase are present in E. coli in large excess relative to RNase E and therefore are detected in cells largely as molecules unlinked to the RNase E scaffold, immunogold labeling and biochemical analyses show that helicase is present in approximately equimolar amounts to RNase E at all cell growth stages. Our findings, which establish the existence and cellular location of RNase E-based degradosomes in vivo in E. coli, also suggest that RNA processing and decay may occur at specific sites within cells.

• Publisher: National Academy of Sciences,National Acad Sciences,The National Academy of Sciences
• Subject: Antibodies / Bacteria / Bacterial Proteins - metabolism / Bacterial Proteins - ultrastructure / Biochemistry / Biological Sciences / Blotting, Western / Cell growth / Cell Membrane - metabolism / Cell Membrane - ultrastructure / Cell membranes / Cellular immunity / Cultured cells / degradosomes / E coli / Endoribonucleases - chemistry / Endoribonucleases - isolation & purification / Endoribonucleases - metabolism / Endoribonucleases - ultrastructure / Escherichia coli / Escherichia coli - cytology / Escherichia coli - enzymology / Escherichia coli - metabolism / Escherichia coli - ultrastructure / Freeze Fracturing / Gels / Genetics / Immunohistochemistry / Membrane Proteins - metabolism / Membrane Proteins - ultrastructure / Microscopy, Electron / Molecular biology / Multienzyme Complexes - isolation & purification / Multienzyme Complexes - metabolism / Multienzyme Complexes - ultrastructure / P branes / polynucleotide phosphorylase / Polyribonucleotide Nucleotidyltransferase - isolation & purification / Polyribonucleotide Nucleotidyltransferase - metabolism / Polyribonucleotide Nucleotidyltransferase - ultrastructure / Protein Binding / Proteins / RhlB protein / ribonuclease E / Ribonucleic acid / RNA / RNA helicase / RNA Helicases - isolation & purification / RNA Helicases - metabolism / RNA Helicases - ultrastructure / RNA, Bacterial - metabolism / Room temperature