The RFA regulatory sequence-binding protein in the promoter of

To assure what sequence associated with the androgen regulation, a 15 bp region at the upstream of the ARE of prostate-specific antigen (PSA) promoter, termed RFA, was found in-dispensable for androgen receptor (AR)-mediated transactivation of PSA promoter. In transfection and CAT assays, some nucleotides substitution in RFA could significantly decrease the androgen inducibility for PSA promoter. The in vitro DNA binding assay demonstrated that RFA bound spe-cifically with some non-receptor protein factors in prostate cell nucleus, but the mutant type of RFA lost this ability, so RFA might be a novel accessory cis-element. The RFA-binding proteins were isolated and purified by affinity chromatography using RFA probes. SDS-PAGE and preliminary protein identification showed these proteins possessed sequence high homology with multifunc-tional protein heterogeneous nuclear ribonucleoprotein A1, A2 (hnRNP A1, A2). RFA-binding pro-teins possibly cooperate with AR-mediated transactivation for PSA promoter as coactivator. The study results will facilitate further understanding the mechanism and tissue specificity of PSA pro-moter.