Isolation of XAB2 complex involved in pre-mRNA splicing, transcription, and transcription-coupled repair.
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.
Kuraoka
Isao
I
Laboratories for Organismal Biosystems, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan. ikuraoka@nk-cc.go.jp
Ito
Shinsuke
S
Wada
Tadashi
T
Hayashida
Mika
M
Lee
Lily
L
Saijo
Masafumi
M
Nakatsu
Yoshimichi
Y
Matsumoto
Megumi
M
Matsunaga
Tsukasa
T
Handa
Hiroshi
H
Qin
Jun
J
Nakatani
Yoshihiro
Y
Tanaka
Kiyoji
K
D002460:Cell Line; D003057:Cockayne Syndrome / Q000235:genetics; D004249:DNA Damage; D004260:DNA Repair; D018076:DNA, Complementary / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007668:Kidney; D010957:Plasmids; D012319:RNA Polymerase II / Q000378:metabolism; D012322:RNA Precursors / Q000235:genetics*; D012326:RNA Splicing; D000072260:RNA Splicing Factors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D014158:Transcription, Genetic
D018076:DNA, Complementary; D012322:RNA Precursors; D000072260:RNA Splicing Factors; D014157:Transcription Factors; C417244:XAB2 protein, human; D012319:RNA Polymerase II