poc1:: An Arabidopsis mutant perturbed in phytochrome signaling because of a T DNA insertion in the promoter of PIF3, a gene encoding a phytochrome-interacting bHLH protein
poc1:: An Arabidopsis mutant perturbed in phytochrome signaling because of a T DNA insertion in the promoter of PIF3, a gene encoding a phytochrome-interacting bHLH protein
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DOI：
10.1073/pnas.96.10.5832
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发表时间：
1999-05-11
影响因子：
11.1
通讯作者：
Quail, PH
中科院分区：
文献类型：
--
作者：
Halliday, KJ;Hudson, M;Quail, PH
光敏色素家族的信息光感受器在调节光响应基因的表达中具有重要作用，但细胞内信号转导的机制仍然是难以捉摸的。在一个遗传筛选的T DNA标记的拟南芥突变体的影响，在早期的信号中间体，我们确定了豆荚（光电流1），表现出增强的响应红光。在phyB（光敏色素B）无效突变体的背景中没有这种表型，表明poc1突变增强了phyB信号转导。突变体表型似乎是由于插入诱导的过表达，该基因在红光生长的幼苗，与PIF3作为一个积极作用的信号中间体的功能一致。这些发现，结合从一个单独的酵母双杂交筛选，确定PIF3作为光敏色素相互作用的正常信号传导所必需的因子的数据，提供证据表明光敏色素信号转导可能包括一个直接的途径，光响应核基因通过物理相互作用的感光分子与潜在的转录调节因子PIF3。
The phytochrome family of informational photoreceptors has a central role in regulating light-responsive gene expression, but the mechanism of intracellular signal transduction has remained elusive. In a genetic screen for T DNA-tagged Arabidopsis mutants affected in early signaling intermediates, we identified pod (photocurrent 1), which exhibits enhanced responsiveness to red light. This phenotype is absent in a phyB (phytochrome B) null mutant background, indicating that the poc1 mutation enhances phyB signal transduction, The T DNA insertion in pod was found to be located in the promoter region of PIF3, a gene encoding a basic helix-loop-helix protein. The mutant phenotype seems to result from insertion-induced overexpression of this gene in red-light-grown seedlings, consistent with PIF3 functioning as a positively acting signaling intermediate. These findings, combined with data from a separate yeast two-hybrid screen that identified PIF3 as a phytochrome-interacting factor necessary for normal signaling, provide evidence that phytochrome signal transduction may include a direct pathway to photoresponsive nuclear genes via physical interaction of the photoreceptor molecules with the potential transcriptional regulator PIF3.