title: Real-time imaging of cotranscriptional splicing reveals a kinetic model that reduces noise: implications for alternative splicing regulation.
abstract: Splicing is a key process that expands the coding capacity of genomes. Its kinetics remain poorly characterized, and the distribution of splicing time caused by the stochasticity of single splicing events is expected to affect regulation efficiency. We conducted a small-scale survey on 40 introns in human cells and observed that most were spliced cotranscriptionally. Consequently, we constructed a reporter system that splices cotranscriptionally and can be monitored in live cells and in real time through the use of MS2-GFP. All small nuclear ribonucleoproteins (snRNPs) are loaded on nascent pre-mRNAs, and spliceostatin A inhibits splicing but not snRNP recruitment. Intron removal occurs in minutes and is best described by a model where several successive steps are rate limiting. Each pre-mRNA molecule is predicted to require a similar time to splice, reducing kinetic noise and improving the regulation of alternative splicing. This model is relevant to other kinetically controlled processes acting on few molecules.
authors.affiliation: Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique UMR 5535, 34293 Montpellier Cedex 5, France.
authors.forename: Ute
authors.initials: U
authors.lastname: Schmidt
authors.forename: Eugenia
authors.initials: E
authors.lastname: Basyuk
authors.forename: Marie-Cécile
authors.initials: MC
authors.lastname: Robert
authors.forename: Minoru
authors.initials: M
authors.lastname: Yoshida
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Villemin
authors.forename: Didier
authors.initials: D
authors.lastname: Auboeuf
authors.forename: Stuart
authors.initials: S
authors.lastname: Aitken
authors.forename: Edouard
authors.initials: E
authors.lastname: Bertrand
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D045744:Cell Line, Tumor; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D057054:Molecular Imaging / Q000379:methods*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D017412:Ribonucleoprotein, U1 Small Nuclear