title: Identification of a small molecule inhibitor that stalls splicing at an early step of spliceosome activation.
abstract: Small molecule inhibitors of pre-mRNA splicing are important tools for identifying new spliceosome assembly intermediates, allowing a finer dissection of spliceosome dynamics and function. Here, we identified a small molecule that inhibits human pre-mRNA splicing at an intermediate stage during conversion of pre-catalytic spliceosomal B complexes into activated Bactcomplexes. Characterization of the stalled complexes (designated B028) revealed that U4/U6 snRNP proteins are released during activation before the U6 Lsm and B-specific proteins, and before recruitment and/or stable incorporation of Prp19/CDC5L complex and other Bactcomplex proteins. The U2/U6 RNA network in B028complexes differs from that of the Bactcomplex, consistent with the idea that the catalytic RNA core forms stepwise during the B to Bacttransition and is likely stabilized by the Prp19/CDC5L complex and related proteins. Taken together, our data provide new insights into the RNP rearrangements and extensive exchange of proteins that occurs during spliceosome activation.
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Anzhalika
authors.initials: A
authors.lastname: Sidarovich
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Cindy L
authors.identifier: 0000-0003-0012-9106
authors.initials: CL
authors.lastname: Will
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Anokhina
authors.affiliation: Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
authors.forename: Javier
authors.initials: J
authors.lastname: Ceballos
authors.affiliation: Compound Management and Screening Center, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
authors.forename: Sonja
authors.identifier: 0000-0003-0854-4507
authors.initials: S
authors.lastname: Sievers
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Dmitry E
authors.initials: DE
authors.lastname: Agafonov
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Timur
authors.initials: T
authors.lastname: Samatov
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Penghui
authors.initials: P
authors.lastname: Bao
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Berthold
authors.initials: B
authors.lastname: Kastner
authors.affiliation: Bioanalytics Group, Institute for Clinical Chemistry Göttingen, University Medical Center, Göttingen, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Urlaub
authors.affiliation: Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Waldmann
authors.affiliation: Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Reinhard
authors.identifier: 0000-0003-3253-7518
authors.initials: R
authors.lastname: Lührmann
mesh_terms: D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000302:isolation & purification*; D006801:Humans; D012322:RNA Precursors / Q000378:metabolism; D012326:RNA Splicing / Q000187:drug effects*; D017381:Spliceosomes / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D012322:RNA Precursors
keywords: biochemistry; cell biology; human; pre-mRNA splicing; small molecule inhibitor; spliceosome