Protein capable of binding to the upstream gene of the CYP2B subfamily P450

苯巴比妥对大鼠和豚鼠肝脏细胞色素P450的诱导程度有很大差异。为了回答这一差异，我们比较了两种动物的蛋白质与CYP2B1基因-89~-73bp的寡核苷酸探针(Barbie Box)的结合情况。以肝细胞核提取液为蛋白质组分，苯巴比妥预处理大鼠的所有制剂均与Barbie盒结合较强，而未处理大鼠的许多制剂仅具有较弱的活性。而苯巴比妥对豚鼠肝核抽提物的结合力无明显增加。因此，苯巴比妥对大鼠和豚鼠核蛋白-探针相互作用的反应明显不同。由于这种差异与大鼠和豚鼠细胞色素P450蛋白诱导性的差异有关，提示细胞色素P450的表达和诱导与细胞核…的相互作用有关。更多的是R蛋白和芭比盒基因的区域。还检测了化学效应剂、加热和蛋白酶处理对探针与大鼠核蛋白结合的影响。结果表明：1)钙离子和镁离子有效地增加了结合；2)氯化血红素和曲拉通X-100增加了结合，而苯巴比妥和地塞米松没有增加结合；3)核蛋白抵抗热变性直到60。C和蛋白水解酶的作用。而与豚鼠肝核抽提物结合时，前两种作用不明显或程度有限。能够与探针结合的豚鼠蛋白对加热的稳定性较差，对蛋白酶的敏感性高于大鼠蛋白。在大鼠和豚鼠体内比较了胞浆结合芭比盒的能力，并报道了结果。通过检测豚鼠蛋白(BBBP-GP)与DNA探针的结合活性，从肝细胞核提取液中纯化出BBBP-GP。最小分子量估计为27,000。大鼠核蛋白也得到了纯化，但只是部分纯化。N端序列分析表明，BBBP-gp是一种新的蛋白质。该蛋白与寡核苷酸探针相互作用，但移动的条带被拉长。较少

The extent in the induction of hepatic CYP2B P-450 with phenobarbital is greatly different in rats and guinea pigs. To answer this difference the binding of protein to the oligonucleotide probe of-89 to-73 bp region (Barbie box) of CYP2B1 gene was compared in both animal species. When the nuclear extracts of liver were used as the protein fraction, all preparations from phenobarbital-pretreated rats showed strong binding to the Barbie box, but many preparations from untreated rats had only weak activities. On the contrary, the binding with liver nuclear extracts of guinea pigs was not increased by phenobarbital treatment. Therefore, the response to phenobarbital treatment on the nuclear protein-probe interaction was markedly different in rats and guinea pigs. Since this difference correlated with the contrast of the inducibility between rat and guinea pig CYP2B P-450 protein, it was suggested that the expression and induction of the CYP2B P-450 is related with the interaction of nuclea … More r proteins and Barbie box region of the gene. Alteration of the binding between the probe and rat nuclear protein with chemical effectors, and by heating and protease treatments was also examined. The results showed that 1)Ca2+ and Mg2+ effectively increase the binding ; 2)hemin and Triton X-100 but not phenobarbital and dexamethasone increase the binding ; and 3)nuclear protein resists to the heat-denaturation until 60。C and to the proteolysis with proteases. On the other hand, the former two effects were not seen or the extents were limited in the binding with guinea pig liver nuclear extracts. The guinea pig protein capable of binding to the probe were less stable against heating and were much sensitive against proteases than rat protein. The ability of cytosol to bind Barbie box was compared in rats and guinea pigs, and the results are also reported. A guinea pig protein (BBBP-GP) was purified from liver nuclear extracts by monitoring its binding activity toward DNA probe to electrophoretically homogeneous. The minimum molecular weight was estimated to be 27,000. Rat nuclear protein was also purified though only partially. The analysis of the N-terminal sequence indicated that BBBP-GP is a new protein. This protein interacted with oligonucleotide probe, but the shifted band was stretched. Less