The generally expressed hnRNP F is involved in a neural-specific pre-mRNA splicing event.
The proteins and RNA regulatory elements that control tissue-specific pre-mRNA splicing in mammalian cells are mostly unknown. In this study, a set of proteins is identified that binds to a splicing regulatory element downstream of the neuron specific c-src N1 exon. This complex of proteins bound specifically to a short RNA containing the regulatory sequence in neuronal extracts that splice the N1 exon. It was not seen in non-neuronal cell extracts that fail to splice this exon. UV-cross-linking experiments identified a neuron-specific 75-kD protein and several nontissue-specific proteins, including the 53-kD heterogeneous nuclear ribonucleoprotein F (hnRNP F), as components of this complex. Although present in both extracts, hnRNP F binds tightly to the RNA only in the neuronal extracts. A mutation in the regulatory RNA sequence, that inhibits N1 splicing in vivo, abolished formation of the neuron-specific complex and the binding of the neuron-specific 75-kD protein. Competition experiments in the two extracts show that the binding of the neuronal protein complex to the src pre-mRNA is required to activate N1 exon splicing in vitro. Antibody inhibition experiments indicate that the hnRNP F protein is a functional part of this complex. The assembly of regulatory complexes from both constitutive and specific proteins is likely to be a general feature of tissue-specific splicing regulation.
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Molecular Biology Institute, University of California at Los Angeles 90024-1662, USA.
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D000818:Animals; D000906:Antibodies; D001483:Base Sequence; D005091:Exons; D016391:Genes, src; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D012322:RNA Precursors; D012326:RNA Splicing; D012333:RNA, Messenger; D016601:RNA-Binding Proteins / Q000032:analysis / Q000737:chemistry; D012045:Regulatory Sequences, Nucleic Acid; D012175:Retinoblastoma / Q000737:chemistry / Q000473:pathology; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D014466:Ultraviolet Rays
D000906:Antibodies; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D009419:Nerve Tissue Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins