大鼠C3基因TATA区结合核蛋白与其转录活性关系的研究

大鼠Ｃ３基因的转录受雄激素调控且只在大鼠腹侧前列腺中表达。本文报道用凝胶电泳带漂移分析和离体ＤＮａｇｅＩ足迹法分析研究了大鼠Ｃ３基因ＴＡＴＡ区结合核蛋白与其组织专一的和雄激素调控的转录活性间的关系。结果表示：相同的（－５０到－１０）４ｂｐ的ＴＡＴＡ区ＤＮＡ片段在不同组织的细胞核中结合的核蛋白是不同的。通过与一个仅在ＴＡＴＡ区－２９．位核苷酸Ａ变为Ｇ的天然存在的不表达的Ｃ３（２）等位基因上此片段的核蛋白结合能力作比较后提示在Ｃ３基因唯一表达的组织—腹侧前列腺中,结合在此区的核蛋白是－２９位Ａ依赖的,而在所研究的不表达组织—肝和睾丸中则否。而且此类蛋白质还可能具有与雄激素调控此基因表达有关的其他反式作用因子相互作用的结构域．

Studies on the Correlation of the TATA-box Binding Proteins of the Rat PSBP C_3 Gene with Its Transcription Activities

The transcription of the rat C3(1) gene is markedly stimulated by testosterone and is confined to the ventral prostate (V. P.). The potential correlation of the TATA-box binding proteins of the C3 gene with its highly tissue-specific and androgen-controlled expression was investigated by using electrophoresis mobility shifting assay (EMSA) and in vitro DNaseI footprinting analysis. The results showed that the nuclear proteins bound on the 40bp C3(1) TATA-box DNA fragment (-50 to-10) appeared in a highly tissue-specific manner.By comparing the protein binding activities of the C3(1) probes with a silent allelic form C3(2)probe which shared sequence homology with only one bp difference in the TATAbox (A to G at-29), it was found that the less of binding activity occurred only in the Y. P. which expresses C3 gene when A was replaced by G at-29. This finding indicated,that the specific-29(A)-dependent binding proteins of the V.P.may have additional domains which fecilitate the binding of androgen receptor or other cofactors involved in androgen regulation of C3 expression.