Grenfell S J, Latchman D S, Thomas N S
Department of Haematology, University College London Medical School, U.K.
Biochem J. 1996 May 1;315 ( Pt 3)(Pt 3):889-93. doi: 10.1042/bj3150889.
The transcription factors Oct-1 and Oct-2 bind differentially to three octamer binding sequences corresponding to the octamer binding site from the H2B promoter [ATGCTAATAA], a simple TAATGARAT motif, found in herpes simplex virus IE4/5 genes [GCGGTAATGAGAT], and a perfect consensus overlapping octamer/TAATGARAT motif [ATGCTAATGAGAT]. By comparing the effects of protein kinase A, protein kinase C and casein kinase 2 in vitro on the binding of Oct-1 and Oct-2 to the three motifs, we show that the actions of these kinases regulate Oct-1 and Oct-2 DNA binding independently of each other in a binding-site-specific manner. Inhibition of cellular phosphatases also regulate Oct-1 and Oct-2 DNA binding in a binding-site-specific manner. Both kinase and phosphatase activity are important for regulating the DNA binding activity of Oct-1 and Oct-2 because, in the presence of phosphatase inhibitors, protein kinase A attenuates the binding of both Oct-1 and Oct-2 to the octamer binding site but enhances binding when phosphatase inhibitors are omitted. Thus the DNA specificity of Oct-1 and Oct-2 can be regulated in vitro by the action of different kinases.
转录因子Oct-1和Oct-2与三个八聚体结合序列的结合情况不同，这三个序列分别对应于H2B启动子的八聚体结合位点[ATGCTAATAA]、在单纯疱疹病毒IE4/5基因中发现的简单TAATGARAT基序[GCGGTAATGAGAT]，以及一个完美的共有重叠八聚体/TAATGARAT基序[ATGCTAATGAGAT]。通过比较蛋白激酶A、蛋白激酶C和酪蛋白激酶2在体外对Oct-1和Oct-2与这三个基序结合的影响，我们发现这些激酶的作用以结合位点特异性的方式彼此独立地调节Oct-1和Oct-2与DNA的结合。抑制细胞磷酸酶也以结合位点特异性的方式调节Oct-1和Oct-2与DNA的结合。激酶和磷酸酶活性对于调节Oct-1和Oct-2的DNA结合活性都很重要，因为在存在磷酸酶抑制剂的情况下，蛋白激酶A会减弱Oct-1和Oct-2与八聚体结合位点的结合，但在省略磷酸酶抑制剂时会增强结合。因此，Oct-1和Oct-2的DNA特异性在体外可通过不同激酶的作用来调节。
