Poly(A)-binding protein positively affects YB-1 mRNA translation through specific interaction with YB-1 mRNA

J Biol Chem. 2003 May 16;278(20):18191-8. doi: 10.1074/jbc.M209073200. Epub 2003 Mar 19.

Abstract

The major protein of cytoplasmic mRNPs from rabbit reticulocytes, YB-1, is a member of an ancient family of proteins containing a common structural feature, cold-shock domain. In eukaryotes, this family is represented by multifunctional mRNA/Y-box DNA-binding proteins that control gene expression at different stages. To address possible post-transcriptional regulation of YB-1 gene expression, we examined effects of exogenous 5'- and 3'-untranslatable region-containing fragments of YB-1 mRNA on its translation and stability in a cell-free system. The addition of the 3' mRNA fragment as well as its subfragment I shut off protein synthesis at the initiation stage without affecting mRNA stability. UV cross-linking revealed four proteins (69, 50, 46, and 44 kDa) that specifically interacted with the 3' mRNA fragment; the inhibitory subfragment I bound two of them, 69- and 50-kDa proteins. We have identified these proteins as PABP (poly(A)-binding protein) (69 kDa) and YB-1 (50 kDa) and demonstrated that titrating out of PABP by poly(A) strongly and specifically inhibits YB-1 mRNA cap(+)poly(A)(-) translation in a cell-free system. Thus, PABP is capable of positively affecting YB-1 mRNA translation in a poly(A) tail-independent manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Northern
  • CCAAT-Enhancer-Binding Proteins / metabolism*
  • Cell-Free System
  • Codon, Terminator
  • DNA, Complementary / metabolism
  • DNA-Binding Proteins*
  • Dose-Response Relationship, Drug
  • Electrophoresis, Polyacrylamide Gel
  • Gene Expression Regulation
  • Globins / metabolism
  • Immunoblotting
  • NFI Transcription Factors
  • Nuclear Proteins
  • Plasmids / metabolism
  • Poly(A)-Binding Proteins / metabolism*
  • Precipitin Tests
  • Protein Binding
  • Protein Biosynthesis*
  • RNA, Messenger / metabolism*
  • Rabbits
  • Reticulocytes / metabolism
  • Sucrose / pharmacology
  • Temperature
  • Time Factors
  • Transcription Factors*
  • Ultraviolet Rays
  • Y-Box-Binding Protein 1

Substances

  • CCAAT-Enhancer-Binding Proteins
  • Codon, Terminator
  • DNA, Complementary
  • DNA-Binding Proteins
  • NFI Transcription Factors
  • Nuclear Proteins
  • Poly(A)-Binding Proteins
  • RNA, Messenger
  • Transcription Factors
  • Y-Box-Binding Protein 1
  • YBX1 protein, human
  • Sucrose
  • Globins