Pierre-Jerome Edith, Moss Britney L, Lanctot Amy, Hageman Amber, Nemhauser Jennifer L
Department of Biology, University of Washington, Seattle, WA 98195.
Department of Biology, University of Washington, Seattle, WA 98195
Proc Natl Acad Sci U S A. 2016 Oct 4;113(40):11354-11359. doi: 10.1073/pnas.1604379113. Epub 2016 Sep 19.
Auxin-regulated transcription pivots on the interaction between the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) repressor proteins and the AUXIN RESPONSE FACTOR (ARF) transcription factors. Recent structural analyses of ARFs and Aux/IAAs have raised questions about the functional complexes driving auxin transcriptional responses. To parse the nature and significance of ARF-DNA and ARF-Aux/IAA interactions, we analyzed structure-guided variants of synthetic auxin response circuits in the budding yeast Saccharomyces cerevisiae Our analysis revealed that promoter architecture could specify ARF activity and that ARF19 required dimerization at two distinct domains for full transcriptional activation. In addition, monomeric Aux/IAAs were able to repress ARF activity in both yeast and plants. This systematic, quantitative structure-function analysis identified a minimal complex-comprising a single Aux/IAA repressing a pair of dimerized ARFs-sufficient for auxin-induced transcription.
生长素调节的转录作用取决于生长素/吲哚 - 3 - 乙酸（Aux/IAA）阻遏蛋白与生长素响应因子（ARF）转录因子之间的相互作用。最近对ARF和Aux/IAA的结构分析引发了关于驱动生长素转录反应的功能复合物的问题。为了解析ARF与DNA以及ARF与Aux/IAA相互作用的性质和意义，我们分析了酿酒酵母中合成生长素响应回路的结构导向变体。我们的分析表明，启动子结构可以决定ARF的活性，并且ARF19需要在两个不同结构域进行二聚化才能实现完全转录激活。此外，单体Aux/IAA能够在酵母和植物中抑制ARF活性。这种系统的、定量的结构 - 功能分析确定了一个最小复合物——由单个Aux/IAA抑制一对二聚化的ARF组成——足以实现生长素诱导的转录。
