Krieg J, Oelgeschläger M, Janknecht R, Lüscher B
Institut für Molekularbiologie, Medizinische Hochschule Hannover, Germany.
Oncogene. 1995 Jun 1;10(11):2221-8.
c-Myb is the prototype of a family of transcription factors characterised by a unique DNA binding domain. Previous analyses have concentrated on truncated versions of c-Myb as it has been very difficult to produce full length c-Myb. To overcome these difficulties we expressed full length c-Myb in HeLa cells using a recombinant vaccinia virus. Partially purified native full length c-Myb bound efficiently and specifically to DNA with a dissociation constant similar to that obtained with bacterially expressed DNA binding domains. No evidence was found for a negative effect of the leucine zipper on DNA binding. Furthermore the DNA binding domain was protease resistant in contrast to the transactivation and negative regulatory domains. Phosphorylation had no apparent effect on this differential protease sensitivity. The increased sensitivity of the C-terminal domain suggests a more open conformation, which may be relevant in the integration of signals and/or in protein-protein interactions.
c-Myb是一类转录因子家族的原型，其特征在于独特的DNA结合结构域。先前的分析集中在c-Myb的截短版本上，因为生产全长c-Myb非常困难。为了克服这些困难，我们使用重组痘苗病毒在HeLa细胞中表达全长c-Myb。部分纯化的天然全长c-Myb能高效且特异性地与DNA结合，其解离常数与细菌表达的DNA结合结构域所获得的解离常数相似。未发现亮氨酸拉链对DNA结合有负面影响的证据。此外，与反式激活结构域和负调控结构域相比，DNA结合结构域对蛋白酶具有抗性。磷酸化对这种不同的蛋白酶敏感性没有明显影响。C末端结构域敏感性的增加表明其构象更加开放，这可能与信号整合和/或蛋白质-蛋白质相互作用有关。
