SsrA tagging of Escherichia coli SecM at its translation arrest sequence.
Details
Serval ID
serval:BIB_EE930EBDA2F4
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
SsrA tagging of Escherichia coli SecM at its translation arrest sequence.
Journal
Journal of Biological Chemistry
ISSN
0021-9258
Publication state
Published
Issued date
2004
Peer-reviewed
Oui
Volume
279
Number
52
Pages
54193-54201
Language
english
Notes
Publication types: Journal Article
Abstract
SecM is expressed from the secM-secA operon and activates the expression of secA in response to secretion defects. The 3'-end of secM encodes an "arrest sequence," which can interact with the ribosomal exit tunnel, preventing complete secM translation under secretion-defective conditions. In a cis-acting manner, ribosome stalling enhances secA translation. Pro(166) is the last residue incorporated when SecM elongation is arrested. We report that secretion deficiencies lead to SsrA tagging of SecM after Pro(166), Gly(165), and likely Arg(163). Northern blot analysis revealed the presence of a truncated secM transcript, likely issued from a secM-secA cleavage. The level of secM transcripts was decreased either when secM translation was totally prevented or when Pro(166) was mutated. However, the accumulation of a truncated secM transcript required secM translation and was prevented when the SecM arrest sequence was inactivated by a point mutation changing Pro(166) to Ala. We suggest that ribosome pausing at the site encoding the arrest sequence is required for formation of the truncated secM mRNA. SsrA tagging affected neither the presence of the secM mRNA nor secA expression, even under translocation-defective conditions. It is therefore likely that SsrA tagging of SecM occurs only after cleavage of secM-secA mRNA within the secM open reading frame encoding the SecM arrest sequence. Accumulation of transcripts expressing arrested SecM generated growth inhibition that was alleviated by the SsrA tagging system. Therefore, SsrA tagging of SecM would rescue ribosomes to avoid excessive jamming of the translation apparatus on stop-less secM mRNA.
Keywords
Adenosine Triphosphatases/genetics, Amino Acid Sequence, Bacterial Proteins/genetics, Blotting, Northern, Blotting, Western, Cytoplasm/chemistry, Escherichia coli/chemistry, Escherichia coli/genetics, Escherichia coli Proteins/chemistry, Escherichia coli Proteins/genetics, Gene Expression, Membrane Transport Proteins/genetics, Molecular Sequence Data, Mutagenesis, Open Reading Frames, Peptide Chain Elongation, Translational, Point Mutation, Protein Biosynthesis, RNA, Bacterial/genetics, RNA, Messenger/analysis, RNA, Messenger/genetics, RNA, Transfer/analysis, RNA, Transfer/genetics, Ribosomes/metabolism, Transcription Factors/chemistry, Transcription Factors/genetics
Pubmed
Web of science
Open Access
Yes
Create date
27/02/2009 15:44
Last modification date
20/08/2019 16:16