The retinoid X receptor(RXR) is a pleiotropic nuclear receptor transcription factor that interacts with a variety of nuclear receptor dimeric partner. RXR binds cognate response elements as a homodimer in the presence of its ligand, 9-cis retinoic acid, or as a heterodimer with other members of the nuclear hormone receptor superfamily including retinoic acid receptors(RAR), thyroid hormone receptors(TR), vitamin D receptors and peroxisome proliferators-activated receptors(PPAR). The RXR family includes three difference isoforms ; RXR α, β, γ . Human RXR α gene is localized on 9q34.9 and encodes two major isoforms(RXR α1, RXR α2). The DNA binding domain of RXR(111-228aa) was over expressed in E.coli and purified by using conventional column chromatography techniques.