Functional specialization of stomatal bHLHs through modification of DNA-binding and phosphoregulation potential
Functional specialization of stomatal bHLHs through modification of DNA-binding and phosphoregulation potential
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DOI：
10.1073/pnas.1411766111
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发表时间：
2014-10-28
影响因子：
11.1
通讯作者：
Bergmann, Dominique C.
中科院分区：
文献类型：
--
作者：
Davies, Kelli A.;Bergmann, Dominique C.
转录因子复制事件和随后的专业化可以通过促进生物创新和发育复杂性来推动进化。鉴定赋予体内不同生物化学功能的序列是理解相关因素如何随着时间的推移改善特定发育过程的重要一步。基本的螺旋-环-螺旋（bHLH）蛋白SPEECHLESS，在拟南芥气孔谱系进展所需的三个密切相关的转录因子之一的功能分析，允许解剖与特定的发展输出的图案。磷酸化残基，以前显示定量影响活动，也允许分裂和细胞命运促进活动之间的功能的定性转变。我们的数据还提供了令人惊讶的证据表明，尽管在DNA结合结构域的深度序列保守，这些结构域的功能要求已经分化，与三个气孔bHLHs表现出绝对的，部分的，或没有要求的DNA结合残基的体内活动。利用这些数据，我们建立了一个合理的模型，描述了这些蛋白质目前独特和重叠的作用可能是如何从一个单一的祖先蛋白质进化而来的。
Transcription factor duplication events and subsequent specialization can drive evolution by facilitating biological innovation and developmental complexity. Identification of sequences that confer distinct biochemical function in vivo is an important step in understanding how related factors could refine specific developmental processes over time. Functional analysis of the basic helix-loop-helix (bHLH) protein SPEECHLESS, one of three closely related transcription factors required for stomatal lineage progression in Arabidopsis thaliana, allowed a dissection of motifs associated with specific developmental outputs. Phosphorylated residues, shown previously to quantitatively affect activity, also allow a qualitative shift in function between division and cell fate-promoting activities. Our data also provide surprising evidence that, despite deep sequence conservation in DNA-binding domains, the functional requirement for these domains has diverged, with the three stomatal bHLHs exhibiting absolute, partial, or no requirements for DNA-binding residues for their in vivo activities. Using these data, we build a plausible model describing how the current unique and overlapping roles of these proteins might have evolved from a single ancestral protein.