TY - JOUR
T1 - Identification of regulatory factor X as a novel mismatch repair stimulatory factor
AU - Zhang, Yanbin
AU - Yuan, Fenghua
AU - Wang, Daojing
AU - Gu, Liya
AU - Li, Guo Min
PY - 2008/5/9
Y1 - 2008/5/9
N2 - This report describes the identification and purification of a novel mismatch repair stimulatory factor from HeLa cell extracts. This activity copurifies with a proliferating cell nuclear antigen-dependent 5′ → 3′DNAexcision activity during several purification steps but is resolved from the excision activity during gel filtration chromatography using Sephacryl S-300. After purification to near homogeneity, the stimulatory factor is associated with three polypeptides with apparent molecular masses of 68, 36, and 30 kDa. Peptide sequencing analysis by tandem mass spectrometry identified the stimulatory factor as the heterotrimeric regulatory factor X (RFX) complex, which regulates transcription of the class II major histocompatibility complex by facilitating histone acetylation and is defective in the human hereditary immunodeficiency syndrome called bare lymphocyte syndrome. This conclusion was confirmed by the facts that purified recombinant RFX stimulates mismatch repair in an in vitro reconstituted mismatch repair system and that depletion of RFX from nuclear extracts or RFX knockdown in cells reduces mismatch repair activity. As expected, RFX knockdown cells display instability in microsatellite sequences. The possible role of RFX in human MMR repair is discussed.
AB - This report describes the identification and purification of a novel mismatch repair stimulatory factor from HeLa cell extracts. This activity copurifies with a proliferating cell nuclear antigen-dependent 5′ → 3′DNAexcision activity during several purification steps but is resolved from the excision activity during gel filtration chromatography using Sephacryl S-300. After purification to near homogeneity, the stimulatory factor is associated with three polypeptides with apparent molecular masses of 68, 36, and 30 kDa. Peptide sequencing analysis by tandem mass spectrometry identified the stimulatory factor as the heterotrimeric regulatory factor X (RFX) complex, which regulates transcription of the class II major histocompatibility complex by facilitating histone acetylation and is defective in the human hereditary immunodeficiency syndrome called bare lymphocyte syndrome. This conclusion was confirmed by the facts that purified recombinant RFX stimulates mismatch repair in an in vitro reconstituted mismatch repair system and that depletion of RFX from nuclear extracts or RFX knockdown in cells reduces mismatch repair activity. As expected, RFX knockdown cells display instability in microsatellite sequences. The possible role of RFX in human MMR repair is discussed.
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U2 - 10.1074/jbc.M800460200
DO - 10.1074/jbc.M800460200
M3 - Article
C2 - 18319249
AN - SCOPUS:45149086930
SN - 0021-9258
VL - 283
SP - 12730
EP - 12735
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 19
ER -