Heterogeneous nuclear ribonucleoprotein (hnRNP) E1 binds to hnRNP A2 and inhibits translation of A2 response element mRNAs.
Heterogeneous nuclear ribonucleoprotein (hnRNP) A2 is a trans-acting RNA-binding protein that mediates trafficking of RNAs containing the cis-acting A2 response element (A2RE). Previous work has shown that A2RE RNAs are transported to myelin in oligodendrocytes and to dendrites in neurons. hnRNP E1 is an RNA-binding protein that regulates translation of specific mRNAs. Here, we show by yeast two-hybrid analysis, in vivo and in vitro coimmunoprecipitation, in vitro cross-linking, and fluorescence correlation spectroscopy that hnRNP E1 binds to hnRNP A2 and is recruited to A2RE RNA in an hnRNP A2-dependent manner. hnRNP E1 is colocalized with hnRNP A2 and A2RE mRNA in granules in dendrites of oligodendrocytes. Overexpression of hnRNP E1 or microinjection of exogenous hnRNP E1 in neural cells inhibits translation of A2RE mRNA, but not of non-A2RE RNA. Excess hnRNP E1 added to an in vitro translation system reduces translation efficiency of A2RE mRNA, but not of nonA2RE RNA, in an hnRNP A2-dependent manner. These results are consistent with a model where hnRNP E1 recruited to A2RE RNA granules by binding to hnRNP A2 inhibits translation of A2RE RNA during granule transport.
Kosturko
Linda D
LD
Department of Neuroscience, Molecular, Microbial, and Structural Biology, and Biomedical Science Graduate Program, University of Connecticut Health Center, Farmington, CT 06030, USA.
Maggipinto
Michael J
MJ
Korza
George
G
Lee
Joo Won
JW
Carson
John H
JH
Barbarese
Elisa
E
D000328:Adult; D000818:Animals; D001710:Biotin; D002478:Cells, Cultured; D003432:Cross-Linking Reagents; D003594:Cytoplasmic Granules / Q000378:metabolism; D004268:DNA-Binding Proteins; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000378:metabolism*; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D008297:Male; D051379:Mice; D009836:Oligodendroglia / Q000166:cytology; D011485:Protein Binding; D014176:Protein Biosynthesis; D021381:Protein Transport; D034443:RNA Transport; D012333:RNA, Messenger / Q000235:genetics*; D016601:RNA-Binding Proteins; D051381:Rats; D020218:Response Elements / Q000235:genetics*; D013050:Spectrometry, Fluorescence; D020798:Two-Hybrid System Techniques
D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C094604:PCBP1 protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C439768:hnRNP A2; D001710:Biotin