Inducers of Erythroleukemic Differentiation Cause Messenger RNAs That Lack Poly(A)-binding Protein to Accumulate in Translationally Inactive, Salt-labile 80 S Ribosomal Complexes
Translation has an established role in the regulation of cell growth. Posttranslational modification of translation initiation and elongation factors or regulation of mRNA polyadenylation represent common means of regulating translation in response to mitogenic or developmental signals. Induced diff...
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Published in | The Journal of biological chemistry Vol. 271; no. 38; pp. 23246 - 23254 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
United States
American Society for Biochemistry and Molecular Biology
20.09.1996
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Subjects | |
Online Access | Get full text |
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Summary: | Translation has an established role in the regulation of cell growth. Posttranslational modification of translation initiation
and elongation factors or regulation of mRNA polyadenylation represent common means of regulating translation in response
to mitogenic or developmental signals. Induced differentiation of Friend virus-transformed erythroleukemia cells is accompanied
by a rapid decrease in the translation rate of these cells. Although inducers do not alter initiation factor modifications,
characterization of their effect on mRNA translation provides evidence that this is mediated by the poly(A)-binding protein
(PABP). Inducer exposure results in an increase in the amount of mRNA that sediments at 80 S and a decrease in the amount
in polysomes. Although these 80 S ribosomes have characteristics previously attributed to âvacant ribosomal couples,â including
lability in 500 m KCl and an inability to incorporate amino acids into protein, we provide evidence that these 80 S complexes
are not vacant but contain mRNA that is stably bound to the 40 S subunit, whereas the 60 S subunit is dissociated from the
complex by high salt. The absence of eukaryotic initiation factor 2 from these complexes suggests that translation has proceeded
through subunit joining. Immunoblotting demonstrates that the mRNAs in these 80 S ribosomal complexes do not contain bound
PABP and that this protein is found to be almost exclusively associated with translating polysomes. These data suggest that
the PABP plays a role in the accumulation of these 80 S ribosomal·mRNA complexes and may facilitate the formation of translationally
active salt-stable ribosomes. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.271.38.23246 |