Small nuclear ribonucleoprotein remodeling during catalytic activation of the spliceosome.
Major structural changes occur in the spliceosome during its activation just before catalyzing the splicing of pre-messenger RNAs (pre-mRNAs). Whereas changes in small nuclear RNA (snRNA) conformation are well documented, little is known about remodeling of small nuclear ribonucleoprotein (snRNP) structures during spliceosome activation. Here, human 45S activated spliceosomes and a previously unknown 35S U5 snRNP were isolated by immunoaffinity selection and were characterized by mass spectrometry. Comparison of their protein components with those of other snRNP and spliceosomal complexes revealed a major change in protein composition during spliceosome activation. Our data also suggest that the U5 snRNP is dramatically remodeled at this stage, with the Prp19 complex and other factors tightly associating, possibly in exchange for other U5 proteins, and suggest that after catalysis the remodeled U5 is eventually released from the postsplicing complex as a 35S snRNP particle.
Makarov
Evgeny M
EM
Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, D-37077 Göttingen, Germany.
Makarova
Olga V
OV
Urlaub
Henning
H
Gentzel
Marc
M
Will
Cindy L
CL
Wilm
Matthias
M
Lührmann
Reinhard
R
D002384:Catalysis; D002499:Centrifugation, Density Gradient; D006801:Humans; D046911:Macromolecular Substances; D013058:Mass Spectrometry; D008957:Models, Genetic; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism; D056918:Nuclear Receptor Coactivators; D011233:Precipitin Tests; D012322:RNA Precursors / Q000378:metabolism; D012326:RNA Splicing; D012342:RNA, Small Nuclear / Q000378:metabolism; D017415:Ribonucleoprotein, U5 Small Nuclear / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D017381:Spliceosomes / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors
D046911:Macromolecular Substances; D009687:Nuclear Proteins; D056918:Nuclear Receptor Coactivators; D012322:RNA Precursors; D012342:RNA, Small Nuclear; D017415:Ribonucleoprotein, U5 Small Nuclear; C111791:SNW1 protein, human; D014157:Transcription Factors