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J Biol Chem. 2008 Jan 11;283(2):940-50. Epub 2007 Nov 2.

Isolation of XAB2 complex involved in pre-mRNA splicing, transcription, and transcription-coupled repair.

Author information

1
Laboratories for Organismal Biosystems, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan. ikuraoka@nk-cc.go.jp

Abstract

Nucleotide excision repair is a versatile repair pathway that counteracts the deleterious effects of various DNA lesions. In nucleotide excision repair, there is a transcription-coupled repair (TCR) pathway that focuses on DNA damage that blocks RNA polymerase IIo in transcription elongation. XAB2 (XPA-binding protein 2), containing tetratricopeptide repeats, has been isolated by virtue of its ability to interact with xeroderma pigmentosum group A protein (XPA). Moreover, XAB2 has been shown to interact with Cockayne syndrome group A and B proteins (CSA and CSB) and RNA polymerase II, as well as XPA, and is involved in TCR and transcription. Here we purified XAB2 as a multimeric protein complex consisting of hAquarius, XAB2, hPRP19, CCDC16, hISY1, and PPIE, which are involved in pre-mRNA splicing. Knockdown of XAB2 with small interfering RNA in HeLa cells resulted in a hypersensitivity to killing by UV light and a decreased recovery of RNA synthesis after UV irradiation and regular RNA synthesis. Enhanced interaction of XAB2 with RNA polymerase IIo or XPA was observed in cells treated with DNA-damaging agents, indicating DNA damage-responsive activity of the XAB2 complex. These results indicated that the XAB2 complex is a multifunctional factor involved in pre-mRNA splicing, transcription, and TCR.

PMID:
17981804
DOI:
10.1074/jbc.M706647200
[Indexed for MEDLINE]
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