PT  - JOURNAL ARTICLE
AU  - Makarov, Evgeny M.
AU  - Makarova, Olga V.
AU  - Urlaub, Henning
AU  - Gentzel, Marc
AU  - Will, Cindy L.
AU  - Wilm, Matthias
AU  - Lührmann, Reinhard
TI  - Small Nuclear Ribonucleoprotein Remodeling During Catalytic Activation of the Spliceosome
AID  - 10.1126/science.1077783
DP  - 2002 Dec 13
TA  - Science
PG  - 2205--2208
VI  - 298
IP  - 5601
4099  - http://science.sciencemag.org/content/298/5601/2205.short
4100  - http://science.sciencemag.org/content/298/5601/2205.full
SO  - Science2002 Dec 13; 298
AB  - 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.