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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
15
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pubmed:dateCreated |
1975-11-6
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pubmed:abstractText |
It is shown that factor i, a bacterial protein, specifically inhibits that step in the initiation of R17 bacteriophage RNA translation that involves the attachment of native R17 RNA to 30 S ribosomal subunits carrying fMet-tRNA. This inhibition by factor i is relieved by the addition of excess R17 RNA, but not by the addition of excess 30 S subunits. That R17 RNA is the only target of the inhibition is demonstrated further by the fact that in a cell-free extract containing all components for protein synthesis, factor i-mediated inhibition of exogenous R17 RNA translation can be overcome only by the addition of excess R17 RNA and not by excess cell-free extract. Upon relief of inhibition, phage coat protein synthesis is restored; enhancement of formation of other cistron products is not seen. While initiation of R17 RNA translation is blocked by factor i, chain elongation is not affected. Although foactor i inhibits the IF-3-dependent binding of R17 RNA to fMet-tRNA-30 S complexes, under conditions of initiation of protein synthesis formation of stable complexes between factor i and IF-3 could not be detected, and factor i did not interfere with the binding of IF-3 to free, native R17 RNA. Instead of affecting the function of IF-3 or ribosomes, factor i exerts its inhibition by binding to R17 RNA and acting as a translational repressor. Factor i prefers intact R17 RNA to fragments generated by autoradiolysis; its binding to R17 RNA is specific in that little competition is observed by transfer RNA, ribosomal RNA or poly(A). However, factor i has a high affinity for poly(U) sequences.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Aug
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
10
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pubmed:volume |
250
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
5749-55
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:1097443-Bacterial Proteins,
pubmed-meshheading:1097443-Binding Sites,
pubmed-meshheading:1097443-Centrifugation, Density Gradient,
pubmed-meshheading:1097443-Coliphages,
pubmed-meshheading:1097443-Electrophoresis, Polyacrylamide Gel,
pubmed-meshheading:1097443-Escherichia coli,
pubmed-meshheading:1097443-Kinetics,
pubmed-meshheading:1097443-Protein Binding,
pubmed-meshheading:1097443-Protein Biosynthesis,
pubmed-meshheading:1097443-RNA, Messenger,
pubmed-meshheading:1097443-RNA, Viral,
pubmed-meshheading:1097443-RNA Viruses,
pubmed-meshheading:1097443-Ribosomes,
pubmed-meshheading:1097443-Time Factors,
pubmed-meshheading:1097443-Transfer RNA Aminoacylation,
pubmed-meshheading:1097443-Viral Proteins
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pubmed:year |
1975
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pubmed:articleTitle |
Translational repression of a viral messenger RNA by a host protein.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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