van der Vliet P C, Verrijzer C P
Laboratory for Physiological Chemistry, University of Utrecht, Vondellaan, The Netherlands.
Bioessays. 1993 Jan;15(1):25-32. doi: 10.1002/bies.950150105.
An increasing number of transcription factors both from prokaryotic and eukaryotic sources are found to bend the DNA upon binding to their recognition site. Bending can easily be detected by the anomalous electrophoretic behaviour of the DNA-protein complex or by increased cyclization of DNA fragments containing the protein-induced bend. Induction of DNA bending by transcription factors could regulate transcription in various ways. Bending may bring distantly bound transcription factors closer together by facilitating DNA-looping or it could mediate the interaction between transcription factors and the general transcription machinery by formation of large nucleoprotein structures in which the DNA is wrapped around the protein complex. Alternatively, the energy stored in a protein-induced bend could be used to favour formation of an open transcription complex or to dissociate the RNA polymerase in the transition from initiation to elongation. Modification of the bend angles and bending centers, caused by homodimerization or heterodimerization of transcription factors, may well turn out to be an important way to enlarge the range of interactions required for regulation of gene expression.
越来越多来自原核生物和真核生物的转录因子被发现，它们在与识别位点结合时会使DNA弯曲。通过DNA - 蛋白质复合物异常的电泳行为，或者通过含有蛋白质诱导弯曲的DNA片段环化增加，都能很容易地检测到DNA弯曲。转录因子诱导的DNA弯曲可以通过多种方式调节转录。弯曲可能通过促进DNA环化使远距离结合的转录因子靠得更近，或者通过形成大型核蛋白结构来介导转录因子与通用转录机制之间的相互作用，在这种结构中DNA缠绕在蛋白质复合物周围。另外，蛋白质诱导弯曲中储存的能量可用于促进开放转录复合物的形成，或在从起始到延伸的转变过程中使RNA聚合酶解离。由转录因子的同二聚化或异二聚化引起的弯曲角度和弯曲中心的改变，很可能成为扩大基因表达调控所需相互作用范围的重要方式。
