Spliceostatin A targets SF3b and inhibits both splicing and nuclear retention of pre-mRNA.
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.
Kaida
Daisuke
D
Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Motoyoshi
Hajime
H
Tashiro
Etsu
E
Nojima
Takayuki
T
Hagiwara
Masatoshi
M
Ishigami
Ken
K
Watanabe
Hidenori
H
Kitahara
Takeshi
T
Yoshida
Tatsuhiko
T
Nakajima
Hidenori
H
Tani
Tokio
T
Horinouchi
Sueharu
S
Yoshida
Minoru
M
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
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