title: Spliceostatin A targets SF3b and inhibits both splicing and nuclear retention of pre-mRNA.
abstract: The removal of intervening sequences from transcripts is catalyzed by the spliceosome, a multicomponent complex that assembles on the newly synthesized pre-mRNA. Pre-mRNA translation in the cytoplasm leads to the generation of aberrant proteins that are potentially harmful. Therefore, tight control to prevent undesired pre-mRNA export from the nucleus and its subsequent translation is an essential requirement for reliable gene expression. Here, we show that the natural product FR901464 (1) and its methylated derivative, spliceostatin A (2), inhibit in vitro splicing and promote pre-mRNA accumulation by binding to SF3b, a subcomplex of the U2 small nuclear ribonucleoprotein in the spliceosome. Importantly, treatment of cells with these compounds resulted in leakage of pre-mRNA to the cytoplasm, where it was translated. Knockdown of SF3b by small interfering RNA induced phenotypes similar to those seen with spliceostatin A treatment. Thus, the inhibition of pre-mRNA splicing during early steps involving SF3b allows unspliced mRNA leakage and translation.
authors.affiliation: Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kaida
authors.forename: Hajime
authors.initials: H
authors.lastname: Motoyoshi
authors.forename: Etsu
authors.initials: E
authors.lastname: Tashiro
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nojima
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hagiwara
authors.forename: Ken
authors.initials: K
authors.lastname: Ishigami
authors.forename: Hidenori
authors.initials: H
authors.lastname: Watanabe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kitahara
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Yoshida
authors.forename: Hidenori
authors.initials: H
authors.lastname: Nakajima
authors.forename: Tokio
authors.initials: T
authors.lastname: Tani
authors.forename: Sueharu
authors.initials: S
authors.lastname: Horinouchi
authors.forename: Minoru
authors.initials: M
authors.lastname: Yoshida
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D006801:Humans; D010750:Phosphoproteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D011714:Pyrans / Q000494:pharmacology; D012322:RNA Precursors / Q000187:drug effects* / Q000378:metabolism; D012326:RNA Splicing / Q000187:drug effects*; D000072260:RNA Splicing Factors; D034741:RNA, Small Interfering / Q000494:pharmacology; D016601:RNA-Binding Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000037:antagonists & inhibitors* / Q000235:genetics; D013141:Spiro Compounds / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; C104486:FR 901464; D010750:Phosphoproteins; D011714:Pyrans; D012322:RNA Precursors; D000072260:RNA Splicing Factors; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear; C112491:SF3B1 protein, human; C486348:SF3B2 protein, human; C486349:SF3B3 protein, human; C486347:SF3B4 protein, human; D013141:Spiro Compounds