Identification and characterization of the mouse nuclear export factor (Nxf) family members.
TAP/hNXF1 is a key factor that mediates general cellular mRNA export from the nucleus, and its orthologs are structurally and functionally conserved from yeast to humans. Metazoans encode additional proteins that share homology and domain organization with TAP/hNXF1, suggesting their participation in mRNA metabolism; however, the precise role(s) of these proteins is not well understood. Here, we found that the human mRNA export factor hNXF2 is specifically expressed in the brain, suggesting a brain-specific role in mRNA metabolism. To address the roles of additional NXF factors, we have identified and characterized the two Nxf genes, Nxf2 and Nxf7, which together with the TAP/hNXF1's ortholog Nxf1 comprise the murine Nxf family. Both mNXF2 and mNXF7 have a domain structure typical of the NXF family. We found that mNXF2 protein is expressed during mouse brain development. Similar to TAP/hNXF1, the mNXF2 protein is found in the nucleus, the nuclear envelope and cytoplasm, and is an active mRNA export receptor. In contrast, mNXF7 localizes exclusively to cytoplasmic granules and, despite its overall conserved sequence, lacks mRNA export activity. We concluded that mNXF2 is an active mRNA export receptor similar to the prototype TAP/hNXF1, whereas mNXF7 may have a more specialized role in the cytoplasm.
Tan
Wei
W
Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute Frederick, MD 21702-1201, USA.
Zolotukhin
Andrei S
AS
Tretyakova
Irina
I
Bear
Jenifer
J
Lindtner
Susan
S
Smulevitch
Sergey V
SV
Felber
Barbara K
BK
D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000737:chemistry; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000737:chemistry; D019913:Nuclear Localization Signals; D029543:Nucleocytoplasmic Transport Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*
C569386:NXF1 protein, mouse; D019913:Nuclear Localization Signals; D029543:Nucleocytoplasmic Transport Proteins; C502321:Nxf2 protein, mouse; C502322:Nxf7 protein, mouse; D012333:RNA, Messenger; D016601:RNA-Binding Proteins