Poly(A)-binding protein positively affects YB-1 mRNA translation through specific interaction with YB-1 mRNA.
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.
Skabkina
Olga V
OV
Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation.
Skabkin
Maxim A
MA
Popova
Nadezhda V
NV
Lyabin
Dmitry N
DN
Penalva
Luiz O
LO
Ovchinnikov
Lev P
LP
D000818:Animals; D015152:Blotting, Northern; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D002474:Cell-Free System; D018388:Codon, Terminator; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D005914:Globins / Q000378:metabolism; D015151:Immunoblotting; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D010957:Plasmids / Q000378:metabolism; D039102:Poly(A)-Binding Proteins / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014157:Transcription Factors; D014466:Ultraviolet Rays; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D018388:Codon, Terminator; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D039102:Poly(A)-Binding Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D013395:Sucrose; D005914:Globins