Leonard D A, Kerppola T K
Howard Hughes Medical Institute and Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor 48109-0650, USA.
Nat Struct Biol. 1998 Oct;5(10):877-81. doi: 10.1038/2316.
Heterodimeric transcription factors can bind to palindromic recognition elements in two opposite orientations with potentially distinct effects on transcriptional activity. We have determined the orientation of Fos-Jun binding at different AP-1 sites using a novel gel-based fluorescence resonance energy transfer assay. The orientation preference of heterodimer binding varied over a greater than 10-fold range. Single base pair substitutions that alter bending of flanking sequences reversed the orientation of heterodimer binding. Single amino acid substitutions that reduce the difference in DNA bending between Fos and Jun also reduced the orientation preference. Consequently, indirect read-out mediated by differences in DNA structure can contribute to the structural organization of nucleoprotein complexes.
异二聚体转录因子能够以两种相反的方向与回文识别元件结合，这可能对转录活性产生不同的影响。我们使用一种基于凝胶的新型荧光共振能量转移测定法，确定了Fos-Jun在不同AP-1位点的结合方向。异二聚体结合的方向偏好性在超过10倍的范围内变化。改变侧翼序列弯曲度的单碱基对替换会使异二聚体结合的方向发生反转。减少Fos和Jun之间DNA弯曲差异的单氨基酸替换也降低了方向偏好性。因此，由DNA结构差异介导的间接读出可能有助于核蛋白复合物的结构组织。
