transcription/export complex (TREX complex)

Function: - specifically associates with spliced mRNA & not with unspliced pre-mRNA - it is recruited to spliced mRNAs by a transcription- independent mechanism - binds to mRNA upstream of the exon-junction complex & is recruited in a splicing- & cap-dependent manner to a region near the 5' end of the mRNA where it functions in mRNA export - recruitment occurs via an interaction between THOC4 & the cap-binding protein NCBP1 - DDX39B functions as a bridge between THOC4 & the THO complex Structure: - subunits include: THO subcomplex, THOC3, THOC4 & DDX39B Pathology: - essential for the export of Kaposi's sarcoma-associated herpesvirus (KSHV) intronless mRNAs & infectious virus production - recruitment of the TREX complex to intronless viral mRNA occurs via an interaction between KSHV ORF57 protein & THOC4

Properties

SUBUNITS: THO subcomplex THO complex subunit 3 COMPARTMENT: cell nucleus MOTIF: WD repeat {53-94} WD repeat {97-137} WD repeat {139-178} WD repeat {180-221} WD repeat {222-261} WD repeat {264-303} THO complex subunit 4 COMPARTMENT: cell nucleus MOTIF: acetylation site SITE: 1-1 EFFECTOR-BOUND: acetyl glycine-rich region {20-230} MOTIF: RRM {105-182} spliceosome RNA helicase DDX39B COMPARTMENT: cell nucleus MOTIF: acetylation site SITE: N-TERMINUS EFFECTOR-BOUND: acetyl Q motif {45-73} helicase NAME: helicase SITE: 76-249 MOTIF: ATP-binding site NAME: ATP-binding site SITE: 89-96 Thr phosphorylation site {T172} DECD box {196-199} Helicase C-terminal {261-422}

References

UniProt :accession Q13838

Components

spliceosome RNA helicase DDX39B; 56 kD U2AF65-associated protein; ATP-dependent RNA helicase p47; DEAD box protein UAP56; HLA-B-associated transcript 1 protein (DDX39B BAT1 UAP56) THO complex subunit 3 (Tho3, TEX1 homolog, THOC3) THO complex subunit 4; Tho4; Ally of AML-1 & LEF-1; transcriptional coactivator Aly/REF; bZIP-enhancing factor BEF (THOC4, ALY, BEF, ALYREF) THO subcomplex