A translation regulatory particle containing the Xenopus oocyte Y box protein mRNP3+4

In oocytes, nontranslated maternal mRNAs are packaged by protein into messenger ribonucleoprotein particles (mRNPs) that are masked from translation by protein-RNA interactions. Proteins associated with such masked states of mRNAs are particularly abundant in amphibian oocytes. One of these mRNP pro...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 1997-04, Vol.272 (16), p.10870-10876
Main Authors: Yurkova, M S, Murray, M T
Format: Article
Language:English
Subjects:
Animals
Chromatography, Gel
Chromatography, Ion Exchange
Electrophoresis, Polyacrylamide Gel
Female
Gene Expression Regulation
Molecular Weight
Multigene Family
Nuclear Proteins - isolation & purification
Nuclear Proteins - metabolism
Nucleolin
Oocytes - physiology
Phosphoproteins - isolation & purification
Phosphoproteins - metabolism
Protein Biosynthesis
Rabbits
Reticulocytes - metabolism
RNA, Messenger - metabolism
RNA-Binding Proteins - isolation & purification
RNA-Binding Proteins - metabolism
Transcription Factors - isolation & purification
Transcription Factors - metabolism
Xenopus laevis
Xenopus Proteins
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In oocytes, nontranslated maternal mRNAs are packaged by protein into messenger ribonucleoprotein particles (mRNPs) that are masked from translation by protein-RNA interactions. Proteins associated with such masked states of mRNAs are particularly abundant in amphibian oocytes. One of these mRNP proteins from Xenopus oocytes, mRNP3+4 (also called FRG Y2a/b or p54/p56), binds to diverse mRNAs independent of their sequence and is the germ line member of the evolutionarily conserved Y box protein multigene family. Xenopus oocytes contain soluble pools of mRNP3+4 6 S oligomers, probably dimers, and larger approximately 15 S particles containing mRNP3+4 and additional proteins. Here we report the purification of this larger form as an approximately 320-kDa particle that contains mRNP3+4 and nine additional polypeptides, including mRNA-binding polypeptides of 34 and 36 kDa and a doublet of 110/105 kDa that proved to be nucleolin. The particle has a protein kinase activity that phosphorylates its own mRNP3+4, nucleolin, and a 31-kDa polypeptide component and exhibits translational inhibition in both the wheat germ extract and rabbit reticulocyte lysate systems. The presence of mRNP3+4 and nucleolin in this large translation regulatory particle suggests that it participates in an early step of mRNP assembly and masking.
ISSN:0021-9258
DOI:10.1074/jbc.272.16.10870