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Symbol TARBP2 contributors: shn/mct - updated : 28-12-2015
HGNC name TAR (HIV-1) RNA binding protein 2
HGNC id 11569
Location 12q13.13      Physical location : 53.894.704 - 53.900.213
Synonym name
  • TAR (HIV) RNA binding protein 2
  • trans-activation responsive RNA-binding protein
  • loquacious, Drosophila, homolog of
  • Synonym symbol(s) LOQS, TRBP, TRBP1, TRBP2
    TYPE functioning gene
    STRUCTURE 6.23 kb     9 Exon(s)
    10 Kb 5' upstream gene genomic sequence study
    regulatory sequence Promoter (CAAT box)
    Binding site   transcription factor
    text structure several potential binding sites for transcriptional factors
    MAPPING cloned Y linked N status confirmed
    Map cen - D12S359 - D12S1618 - TARBP2 - D12S1586 - D12S1651 - qter
    Authors Kozak (1995)
    Text TARBP2 gene was mapped to 12p12.1-q13.1 by analysis of somatic cell hybrids
    Physical map
    KRT8 12q13 keratin 8 KRT18 12q13 keratin 18 EIF4B 12q13.13 eukaryotic translation initiation factor 4B PRO1843 12q13.13 hypothetical protein PRO1843 TENC1 12q12 tensin like C1 domain-containing phosphatase FLJ14800 12q13.13 hypothetical protein FLJ14800 IGFBP6 12q13 insulin-like growth factor binding protein 6 SOAT2 12q13.13 sterol O-acyltransferase 2 LOC387862 12 hypothetical gene supported by AK130082; NM_001416 CSAD 12q13.11-q14.3 cysteine sulfinic acid decarboxylase LOC390316 12 similar to oriLyt TD-element binding protein 7 ITGB7 12q13.2 integrin, beta 7 MGC11308 12q13.13 hypothetical protein MGC11308 ESPL1 8 extra spindle poles like 1 (S. cerevisiae) PFDN5 12q13.1 prefoldin 5 C12orf10 12q13 chromosome 12 open reading frame 10 AAAS 12q13 achalasia, adrenocortical insufficiency, alacrimia (Allgrove, triple-A) SP7 12q12 Sp7 transcription factor SP1 12q13.1 Sp1 transcription factor AMHR2 12q13 anti-Mullerian hormone receptor, type II DKFZP564J157 12q12 DKFZp564J157 protein PCBP2 12q13.12-q13.13 poly(rC) binding protein 2 MAP3K12 12q13 mitogen-activated protein kinase kinase kinase 12 TARBP2 12q12-q13 TAR (HIV) RNA binding protein 2 NPFF 12q13.13 neuropeptide FF-amide peptide precursor FLJ30317 12q13.13 hypothetical protein FLJ30317 ATF7 12q13 activating transcription factor 7 LOC341412 12q13.13 similar to ribosomal protein L31 ATP5G2 12q13.13 ATP synthase, H+ transporting, mitochondrial F0 complex, subunit c (subunit 9), isoform 2 KIAA1536 12q13.13 KIAA1536 protein HOXC13 12q13.3 homeo box C13 HOXC12 12q13.3 homeo box C12
    TRANSCRIPTS type messenger
    identificationnb exonstypebpproduct
    ProteinkDaAAspecific expressionYearPubmed
    9 splicing 1888 39.1 366 - 2014 24563462
    two adjacent promoters initiate transcription of alternative first exons
    9 splicing 1488 - 345 - 2014 24563462
    two adjacent promoters initiate transcription of alternative first exons
    9 - 1448 - 345 - 2014 24563462
    Type widely
       expressed in (based on citations)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    blood / hematopoieticthymus    
    Reproductivemale systemprostate   
    SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
    cell lineage
    cell lines
    at STAGE
  • three dsRNA-binding domains (dsRBDs), the first and second dsRBDs (dsRBD1 and dsRBD2, respectively) have affinities for dsRNA, whereas the third dsRBD (dsRBD3) binds to DICER1
  • mono polymer heteromer , trimer
    interspecies ortholog to Tarbp2, murine
    ortholog to Tarbp2, Rattus norvegicus
    ortholog to tarbp2, Danio rerio
    homolog to LOC736926, Pan troglodytes
    CATEGORY RNA associated
    SUBCELLULAR LOCALIZATION     intracellular
    basic FUNCTION
  • activating HIV-1 gene expression in synergy with the viral Tat protein
  • TARBP2 enhanced expression of the HIV-1 LTR in human
  • and murine cells
  • facilitating the production of small interfering RNA (siRNA) by Dicer
  • TRBP, inhibits the activity of the interferon-induced protein kinase R (PKR)
  • during development, TRBP has a function in spermatogenesis and growth control
  • TRBP regulates the activation of PKR by controlling its accessibility to the PKR activator (PRKRA)
  • double-stranded RNA (dsRNA)-binding protein, which binds to DiCER1 and is required for the RNA interference pathway
  • TRBP has an oncogenic potential due to its interaction with PKR and the tumor suppressor Merlin induces its degradation by ubiquitination
  • its activities at the molecular level impact the cellular function from normal development to cancer and the response to infections
  • double-stranded RNA-specific diffusion activity of TARBP2 contributes to enhancing siRNA and miRNA processing by DICER1
  • cytoplasmic RISC proteins PRKRA, TARBP2, and DICER1 are steroid receptor RNA activator (SRA) binding nuclear receptor coregulators that target steroid-responsive promoters and regulate nuclear receptor activity and downstream gene expression
  • non-canonical and direct role for TARBP2 in gene expression regulation and regulated RNA destabilization through protein-mediated binding of mRNA structural elements can govern cancer progression
  • RNA-binding protein (RBP) involved in miRNA processing and maturation
    a component
  • PRKRA is associated with a ~500 kDa complex that contains DICER1, AGO2, and TARBP2 and it associates with DICER1 to facilitate the production of small interfering RNA
    small molecule
  • interaction with NF2 (merlin-binding protein)
  • TRBP2 binds to HIV-1 TAR RNA and synergizes with HIV-1 Tat to activate the HIV-1 LTR promoter
  • TRAF4
  • protein kinase R (PKR)
  • dicer-TRBP complex associates with Argonaute-2
  • the tumor suppressor Merlin
  • interacts directly with the DICER1 protein and is required for the stabilization of the DICER1 protein (Melo 2009)
  • AGO2, PRKRA and TARBP2 were required for the efficient functioning of DICER1 in cells, and likely one of the roles of these proteins is to assure better synchronization of cleavages triggered by two RNase III domains of DICER1
  • PRKRA and TARBP2 have distinct effects on DICER1-mediated dsRNA processing
  • interface residues conserved between TARBP2 and PRKRA show that the proteins bind to DICER1 in a similar manner and by mutual exclusion
  • cell & other
    corresponding disease(s)
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    tumoral   LOH    
    in mesothelioma
    tumoral     --over  
    in endometrial cancer metastasis
    tumoral somatic mutation     loss of function
    truncating mutations in tumors with microsatellite instability causing diminished TRBP protein expression and defective processing of miRNAs (Melo 2009)
    tumoral     --over  
    in many cancers such as prostate cancer, cutaneous malignant melanoma, and adrenocortical carcinoma
    tumoral     --low  
    in some cancers including colorectal cancer, gastric cancer, Ewing sarcoma, and upper urinary tract urothelial carcinoma
    Variant & Polymorphism
    Candidate gene
  • breast cancer patients with TARBP2 cytoplasm expression have unfavorable prognosis, and patients of triple-negative breast cancer (TNBC) and late-stage breast cancer with higher cytoplasm TARBP2 expression have an unfavorable prognosis
  • Therapy target
  • mice homozygous for the mutant Prkra allele had defects not only in ear development but also growth, craniofacial development and ovarian structure