Translational repression of EF-1 alpha mRNA in vitro.
In this report we show that when 10,000 x g supernatant extracts of growth arrested murine erythroleukemia (MEL) cells are incubated there is a rapid conversion of essentially all mRNAs to non-translating messenger ribonucleoprotein (RNP) particles. Most of these RNPs are readily translated in an initiation-dependent manner when added to a nuclease-treated rabbit reticulocyte lysate. A notable exception is the RNP containing eucaryotic elongation factor 1 alpha (EF-1 alpha) mRNA. The mRNA for poly(A)-binding protein behaved similarly to EF-1 alpha. Previous work has demonstrated that the translation of both these mRNAs are repressed in vivo when the growth of a number of different mammalian cells is arrested [Slobin L. I. and Jordan, P. (1984) Eur J. Biochem. 145, 1984; Thomas, G. and Thomas, G. (1986) J. Cell Biol. 103, 1986]. Translational activity of EF-1 alpha mRNA could be restored by treating RNP particles with 0.5 M KCl, provided that the RNPs were separated from salt wash by chromatography on oligo(dT)-cellulose. Addition of the salt wash to total MEL cell mRNA significantly and selectively inhibited EF-1 alpha mRNA translation, suggesting that a component of the salt wash acts as a trans-acting translational repressor of EF-1 alpha mRNA.
Department of Biochemistry, University of Mississippi School of Medicine, Jackson 39216.
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Slobin
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Rao
D000818:Animals; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism; D051379:Mice; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000235:genetics*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D012097:Repressor Proteins / Q000502:physiology*; D012261:Ribonucleoproteins / Q000235:genetics*; D015534:Trans-Activators / Q000502:physiology; D014407:Tumor Cells, Cultured
D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D012333:RNA, Messenger; D012097:Repressor Proteins; D012261:Ribonucleoproteins; D015534:Trans-Activators