Heterogeneous nuclear ribonucleoprotein A1 is a novel internal ribosome entry site trans-acting factor that modulates alternative initiation of translation of the fibroblast growth factor 2 mRNA.
Alternative initiation of translation of the human fibroblast growth factor 2 (FGF-2) mRNA at five in-frame CUG or AUG translation initiation codons requires various RNA cis-acting elements, including an internal ribosome entry site (IRES). Here we describe the purification of a trans-acting factor controlling FGF-2 mRNA translation achieved by several biochemical purification approaches. We have identified the heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) as a factor that binds to the FGF-2 5'-leader RNA and that also complements defective FGF-2 translation in vitro in rabbit reticulocyte lysate. Recombinant hnRNP A1 stimulates in vitro translation at the four IRES-dependent initiation codons but has no effect on the cap-dependent initiation codon. Consistent with a role of hnRNP A1 in the control of alternative initiation of translation, short interfering RNA-mediated knock down of hnRNP A1 specifically inhibits translation at the four IRES-dependent initiation codons. Furthermore, hnRNP A1 binds to the FGF-2 IRES, implicating this interaction in the control of alternative initiation of translation.
Bonnal
Sophie
S
INSERM U589, Institut Louis Bugnard, Hopital Rangueil, TSA 50032, 31059 Toulouse Cedex 9, France.
Pileur
Frédéric
F
Orsini
Cécile
C
Parker
Fabienne
F
Pujol
Françoise
F
Prats
Anne-Catherine
AC
Vagner
Stéphan
S
D020121:5' Untranslated Regions / Q000737:chemistry; D001665:Binding Sites; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002845:Chromatography; D003062:Codon; D018387:Codon, Initiator; D003101:Collodion / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D047468:Immunoprecipitation; D013058:Mass Spectrometry; D009841:Oligonucleotides / Q000737:chemistry; D011485:Protein Binding; D014176:Protein Biosynthesis; D012313:RNA / Q000737:chemistry; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015533:Transcriptional Activation; D014466:Ultraviolet Rays
D020121:5' Untranslated Regions; D003062:Codon; D018387:Codon, Initiator; D003432:Cross-Linking Reagents; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D009841:Oligonucleotides; D012333:RNA, Messenger; D011994:Recombinant Proteins; C000619656:hnRNPA1 protein, human; D016222:Fibroblast Growth Factor 2; D012313:RNA; D003101:Collodion; D004247:DNA; D005982:Glutathione Transferase