The nuclear export signal of splicing factor Uap56p interacts with nuclear pore-associated protein Rae1p for mRNA export in Schizosaccharomyces pombe.
Mammalian UAP56 or its homolog Sub2p in Saccharomyces cerevisiae are members of the ATP-dependent RNA helicase family and are required for splicing and nuclear export of mRNA. Previously we showed that in Schizosaccharomyces pombe Uap56p is critical for mRNA export. It links the mRNA adapter Mlo3p, a homolog of Yra1p in S. cerevisiae or Aly in mammals, to nuclear pore-associated mRNA export factor Rae1p. In this study we show that, in contrast to S. cerevisiae, Uap56p in S. pombe is not required for pre-mRNA splicing. The putative RNA helicase function of Uap56p is not required for mRNA export. However, the RNA-binding motif of Uap56p is critical for nuclear export of mRNA. Within Uap56p we identified nuclear import and export signals that may allow it to shuttle between the nucleus and the cytoplasm. We found that Uap56p interacts with Rae1p directly via its nuclear export signal, and this interaction is critical for the nuclear export activity of Uap56p as well as for exporting mRNA. RNA binding and the ability to shuttle between the nucleus and cytoplasm are important features of mRNA export carriers such as HIV-Rev. Our results suggest that Uap56p could function similarly as an export carrier of mRNA in S. pombe.
Thakurta
Anjan G
AG
Basic Research Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
Selvanathan
Saravana P
SP
Patterson
Andrew D
AD
Gopal
Ganesh
G
Dhar
Ravi
R
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D049790:Nuclear Export Signals; D034521:Nuclear Matrix-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D022022:Nuclear Pore / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
D049790:Nuclear Export Signals; D034521:Nuclear Matrix-Associated Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C092953:rae1 protein, S pombe; C503582:Uap56 protein, S pombe; D053487:DEAD-box RNA Helicases