Identity elements used in export of mRNAs.
Different classes of RNA are exported from the nucleus by distinct factors. We demonstrate that U1 snRNA is exported like an mRNA on insertion of a pre-mRNA intron or either sense or antisense mRNA exon sequences. mRNA-specific factors are recruited onto the spliced or elongated U1 RNA whereas U snRNA-specific factors are not, suggesting that an unstructured region of sufficient length in an RNA acts as a dominant determinant of mRNA identity. After export, spliced U1 RNA undergoes cytoplasmic maturation but is not reimported into the nucleus. These data provide insight into mechanisms for discrimination of different classes of nuclear RNA and demonstrate that two RNAs of identical sequence can have distinct cytoplasmic fates depending on their mode of export.
Ohno
Mutsuhito
M
The Institute for Virus Research, Laboratory of Biochemistry, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan. mattaj@emblheidelberg.de
Segref
Alexandra
A
Kuersten
Scott
S
Mattaj
Iain W
IW
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D005091:Exons / Q000235:genetics; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism; D007438:Introns / Q000235:genetics; D009690:Nucleic Acid Conformation; D029543:Nucleocytoplasmic Transport Proteins; D009865:Oocytes / Q000502:physiology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D012342:RNA, Small Nuclear / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism; D016601:RNA-Binding Proteins; D017381:Spliceosomes / Q000378:metabolism; D029867:Xenopus Proteins; D014982:Xenopus laevis
D020690:GTPase-Activating Proteins; D029543:Nucleocytoplasmic Transport Proteins; C407263:Phax protein, mouse; D010750:Phosphoproteins; D012333:RNA, Messenger; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; C513268:RanGAP1 protein, Xenopus; C405483:U1 small nuclear RNA; D029867:Xenopus Proteins; D012343:RNA, Transfer