Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.

We report here the results of experiments designed to identify RNA-binding proteins that might be associated with Trypanosoma brucei polysomes. After some preliminary mass spectrometry of polysomal fractions, we investigated the distributions of selected tagged proteins using sucrose gradients and i...

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Main Authors: Cornelia Klein, Monica Terrao, Diana Inchaustegui Gil, Christine Clayton
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2015-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC4545788?pdf=render
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author Cornelia Klein
Monica Terrao
Diana Inchaustegui Gil
Christine Clayton
author_facet Cornelia Klein
Monica Terrao
Diana Inchaustegui Gil
Christine Clayton
author_sort Cornelia Klein
collection DOAJ
description We report here the results of experiments designed to identify RNA-binding proteins that might be associated with Trypanosoma brucei polysomes. After some preliminary mass spectrometry of polysomal fractions, we investigated the distributions of selected tagged proteins using sucrose gradients and immunofluorescence. As expected, the polysomal fractions contained nearly all annotated ribosomal proteins, the translation-associated protein folding complex, and many translation factors, but also many other abundant proteins. Results suggested that cap-binding proteins EIF4E3 and EIF4E4 were associated with both free and membrane-bound polysomes. The EIF4E binding partners EIF4G4 and EIF4G3 were present but the other EIF4E and EIF4G paralogues were not detected. The dominant EIF4E in the polysomal fraction is EIF4E4 and very few polysomal mRNAs are associated with EIF4G. Thirteen potential mRNA-binding proteins were detected in the polysomes, including the known polysome-associated protein RBP42. The locations of two of the other proteins were tested after epitope tagging: RBP29 was in the nucleus and ZC3H29 was in the cytoplasm. Quantitative analyses showed that specific association of an RNA-binding protein with the polysome fraction in sucrose gradients will not be detected if the protein is in more than 25-fold molar excess over its target binding sites.
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spelling doaj.art-1e55fae925704ab4bbd124801661cfc02022-12-22T00:58:43ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01108e013597310.1371/journal.pone.0135973Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.Cornelia KleinMonica TerraoDiana Inchaustegui GilChristine ClaytonWe report here the results of experiments designed to identify RNA-binding proteins that might be associated with Trypanosoma brucei polysomes. After some preliminary mass spectrometry of polysomal fractions, we investigated the distributions of selected tagged proteins using sucrose gradients and immunofluorescence. As expected, the polysomal fractions contained nearly all annotated ribosomal proteins, the translation-associated protein folding complex, and many translation factors, but also many other abundant proteins. Results suggested that cap-binding proteins EIF4E3 and EIF4E4 were associated with both free and membrane-bound polysomes. The EIF4E binding partners EIF4G4 and EIF4G3 were present but the other EIF4E and EIF4G paralogues were not detected. The dominant EIF4E in the polysomal fraction is EIF4E4 and very few polysomal mRNAs are associated with EIF4G. Thirteen potential mRNA-binding proteins were detected in the polysomes, including the known polysome-associated protein RBP42. The locations of two of the other proteins were tested after epitope tagging: RBP29 was in the nucleus and ZC3H29 was in the cytoplasm. Quantitative analyses showed that specific association of an RNA-binding protein with the polysome fraction in sucrose gradients will not be detected if the protein is in more than 25-fold molar excess over its target binding sites.http://europepmc.org/articles/PMC4545788?pdf=render
spellingShingle Cornelia Klein
Monica Terrao
Diana Inchaustegui Gil
Christine Clayton
Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.
PLoS ONE
title Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.
title_full Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.
title_fullStr Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.
title_full_unstemmed Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.
title_short Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.
title_sort polysomes of trypanosoma brucei association with initiation factors and rna binding proteins
url http://europepmc.org/articles/PMC4545788?pdf=render
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