Pre-mRNA splicing alters mRNP composition: evidence for stable association of proteins at exon-exon junctions.
We provide direct evidence that pre-mRNA splicing alters mRNP protein composition. Using a novel in vitro cross-linking approach, we detected several proteins that associate with mRNA exon-exon junctions only as a consequence of splicing. Immunoprecipitation experiments suggested that these proteins are part of a tight complex around the junction. Two were identified as SRm160, a nuclear matrix-associated splicing coactivator, and hPrp8p, a core component of U5 snRNP and spliceosomes. Glycerol gradient fractionation showed that a subset of these proteins remain associated with mRNA after its release from the spliceosome. These results demonstrate that the spliceosome can leave behind signature proteins at exon-exon junctions. Such proteins could influence downstream metabolic events in vivo such as mRNA transport, translation, and nonsense-mediated decay.
Le Hir
H
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Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263 USA.
Moore
M J
MJ
Maquat
L E
LE
D034961:Antigens, Nuclear; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D005091:Exons; D006367:HeLa Cells; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism; D012322:RNA Precursors / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D017415:Ribonucleoprotein, U5 Small Nuclear / Q000302:isolation & purification / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics* / Q000378:metabolism; D017381:Spliceosomes / Q000378:metabolism
D034961:Antigens, Nuclear; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D017415:Ribonucleoprotein, U5 Small Nuclear; D012261:Ribonucleoproteins; C111710:SRRM1 protein, human; C026452:messenger ribonucleoprotein