Wilson T E, Fahrner T J, Milbrandt J
Department of Pathology, Washington University School of Medicine, St Louis, Missouri 63110.
Mol Cell Biol. 1993 Sep;13(9):5794-804. doi: 10.1128/mcb.13.9.5794-5804.1993.
We examined in detail the DNA interaction of the nuclear receptors NGFI-B and steroidogenic factor 1 (SF-1) by using a series of gain-of-function domain swaps. NGFI-B bound with high affinity as a monomer to a nearly linear DNA molecule. The prototypic zinc modules interacted with a half-site of the estrogen receptor class, and a distinct protein motif carboxy terminal to the zinc modules (the A box) interacted with two A/T base pairs 5' to the half-site. SF-1 bound in the same manner as NGFI-B, with an overlapping but distinct sequence requirement 5' to the half-site. The key features that distinguished the NGFI-B and SF-1 interactions were an amino group in the minor groove of the SF-1 binding sequence and an asparagine in the SF-1 A box. These results define a common mechanism of NGFI-B and SF-1 DNA binding, which may underlie a competitive mechanism of gene regulation in steroidogenic tissues that express these proteins. This monomer-DNA interaction represents a third paradigm of DNA binding by nuclear receptors in addition to direct and inverted dimerization.
我们通过一系列功能获得性结构域交换实验，详细研究了核受体NGFI-B和类固醇生成因子1（SF-1）与DNA的相互作用。NGFI-B以单体形式与一个近乎线性的DNA分子高亲和力结合。典型的锌模块与雌激素受体类的半位点相互作用，锌模块羧基末端的一个独特蛋白质基序（A框）与半位点5'端的两个A/T碱基对相互作用。SF-1与NGFI-B的结合方式相同，在半位点5'端有重叠但不同的序列要求。区分NGFI-B和SF-1相互作用的关键特征是SF-1结合序列小沟中的一个氨基和SF-1 A框中的一个天冬酰胺。这些结果定义了NGFI-B和SF-1与DNA结合的共同机制，这可能是表达这些蛋白质的类固醇生成组织中基因调控竞争机制的基础。这种单体与DNA的相互作用代表了核受体与DNA结合的第三种模式，除此之外还有直接和反向二聚化模式。
