This gene product is a member of a family of proteins characterized by a specific cysteine-rich C-terminal domain, which is involved in transcriptional regulation of viral genome expression. Alternative translation initiation from an upstream non-AUG (GUG), and an in-frame, downstream AUG codon, results in the production of two isoforms, p40 and p32, respectively, which have different subcellular localization; p32 is mainly found in the cytoplasm, whereas p40 is targeted to the nucleolus. Both isoforms have transcriptional regulatory activity that is attributable to the cysteine-rich C-terminal domain. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2009],
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Function:
Domain:The cysteine-rich C-terminus is involved in its granular distribution in the cytoplasm.,Function:Modulates the expression from both cellular and viral promoters. Down-regulates Tat-dependent transcription of the human immunodeficiency virus type 1 (HIV-1) LTR by interacting with HIV-1 Tat and Rev and impairing their nuclear import, probably by rendering the NLS domains inaccessible to importin-beta. Also stimulates activation of human T-cell leukemia virus type I (HTLV-I) LTR. Binds to the axin complex, resulting in an increase in the level of free beta-catenin. Affects axin regulation of the WNT and JNK signaling pathways.,similarity:Belongs to the MDFI family.,subcellular location:Isoform 1 localizes to the nucleolus and also shows a granular distribution in the cytoplasm. Isoform 2 is predominantly distributed throughout the cytoplasm, with only weak expression in the nucleus.,subunit:The C-terminus interacts with HIV-1 Tat and Rev, AXIN1, the histidine-rich region of CCNT1/CYCLIN T and weakly with LEF1.,tissue specificity:Expressed in lymphoid organs (spleen, thymus, peripheral blood leukocytes) as well as prostate, uterus and small intestine.,
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Cellular Localization:
[Isoform 1]: Nucleus, nucleolus. Also shows a granular distribution in the cytoplasm.; [Isoform 2]: Cytoplasm . Weak expression in the nucleus.
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Tissue Expression:
Expressed in lymphoid organs (spleen, thymus, peripheral blood leukocytes) as well as prostate, uterus and small intestine.