hnRNP A/B proteins are required for inhibition of HIV-1 pre-mRNA splicing.
Splicing of the human immunodeficiency virus type 1 (HIV-1) pre-mRNA must be inefficient to provide a pool of unspliced messages which encode viral proteins and serve as genomes for new virions. Negative cis-regulatory elements (exonic splicing silencers or ESSs) are necessary for HIV-1 splicing inhibition. We demonstrate that heterogeneous nuclear ribonucleoproteins (hnRNPs) of the A and B group are trans-acting factors required for the function of the tat exon 2 ESS. Depletion of hnRNP A/B proteins from HeLa cell nuclear extract activates splicing of tat exon 2 pre-mRNA substrate. Splicing inhibition is restored by addition of recombinant hnRNP A/B proteins to the depleted extract. A high-affinity hnRNP A1-binding sequence can substitute functionally for the ESS in tat exon 2. These results demonstrate that hnRNP A/B proteins are required for repression of HIV-1 splicing.
Department of Biology and Center for Molecular Biology of RNA, Sinsheimer Laboratories, University of California Santa Cruz, Santa Cruz, CA 95064, USA.
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Caputi
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Mayeda
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Krainer
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Zahler
D001483:Base Sequence; D001665:Binding Sites; D002467:Cell Nucleus / Q000235:genetics; D005091:Exons / Q000235:genetics; D015967:Gene Expression Regulation, Viral; D015696:Gene Products, tat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054322:tat Gene Products, Human Immunodeficiency Virus
D015696:Gene Products, tat; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D054322:tat Gene Products, Human Immunodeficiency Virus