A nuclear factor, ASC-2, as a cancer-amplified transcriptional coactivator essential for ligand-dependent transactivation by nuclear receptors in vivo.
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Lee SK, Anzick SL, Choi JE, Bubendorf L, Guan XY, Jung YK, Kallioniemi OP, Kononen J, Trent JM, Azorsa D, Jhun BH, Cheong JH, Lee YC, Meltzer PS, Lee JW
A nuclear factor, ASC-2, as a cancer-amplified transcriptional coactivator essential for ligand-dependent transactivation by nuclear receptors in vivo.
J Biol Chem. 1999 Nov 26;274(48):34283-93.
- PubMed ID
- 10567404 [ View in PubMed]
- Abstract
Many transcription coactivators interact with nuclear receptors in a ligand- and C-terminal transactivation function (AF2)-dependent manner. We isolated a nuclear factor (designated ASC-2) with such properties by using the ligand-binding domain of retinoid X receptor as a bait in a yeast two-hybrid screening. ASC-2 also interacted with other nuclear receptors, including retinoic acid receptor, thyroid hormone receptor, estrogen receptor alpha, and glucocorticoid receptor, basal factors TFIIA and TBP, and transcription integrators CBP/p300 and SRC-1. In transient cotransfections, ASC-2, either alone or in conjunction with CBP/p300 and SRC-1, stimulated ligand-dependent transactivation by wild type nuclear receptors but not mutant receptors lacking the AF2 domain. Consistent with an idea that ASC-2 is essential for the nuclear receptor function in vivo, microinjection of anti-ASC-2 antibody abrogated the ligand-dependent transactivation of retinoic acid receptor, and this repression was fully relieved by coinjection of ASC-2-expression vector. Surprisingly, ASC-2 was identical to a gene previously identified during a search for genes amplified and overexpressed in breast and other human cancers. From these results, we concluded that ASC-2 is a bona fide transcription coactivator molecule of nuclear receptors, and its altered expression may contribute to the development of cancers.