ARABIDOPSIS HY8 LOCUS ENCODES PHYTOCHROME-A
ARABIDOPSIS HY8 LOCUS ENCODES PHYTOCHROME-A
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DOI：
10.1105/tpc.5.9.1081
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发表时间：
1993-09-01
期刊：
影响因子：
11.6
通讯作者：
QUAIL, PH
中科院分区：
文献类型：
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作者：
DEHESH, K;FRANCI, C;QUAIL, PH
拟南芥的hy8长下胚轴突变体对长时间远红光的反应有缺陷（所谓的“远红高辐照度反应”），选择性地缺乏功能性光敏色素A。为了确定这些突变体中的分子损伤，我们对携带两类hy8等位基因中的一类或另一类的品系中的光敏色素A基因（phyA）进行了测序。表达不可检测的光敏色素 A 的 hy8-1 和 hy8-2 突变体各自具有单个核苷酸变化，在蛋白质编码序列中插入翻译终止密码子。这些结果证实 phyA 位于 HY8 基因座。表达野生型水平的光化学活性光敏色素 A 的 hy8-3 突变体在 phyA 序列 C 端结构域的残基 727 处具有甘氨酸到谷氨酸的错义突变。定量注量率响应分析表明，hy8-3 产生的突变型光敏色素 A 分子没有表现出高于 phyA 蛋白缺陷型 hy8-2 突变体的可检测的调节活性。该结果表明，在所有测序的光敏色素中不变的甘氨酸-727具有对光敏色素A的调节活性重要但对光感知不重要的功能。
hy8 long hypocotyl mutants of Arabidopsis defective in responsiveness to prolonged far-red light (the so-called ''far-red high-irradiance response'') are selectively deficient in functional phytochrome A. To define the molecular lesion in these mutants, we sequenced the phytochrome A gene (phyA) in lines carrying one or other of two classes of hy8 alleles. The hy8-1 and hy8-2 mutants that express no detectable phytochrome A each have a single nucleotide change that inserts a translational stop codon in the protein coding sequence. These results establish that phyA resides at the HY8 locus. The hy8-3 mutant that expresses wild-type levels of photochemically active phytochrome A has a glycine-to-glutamate missense mutation at residue 727 in the C-terminal domain of the phyA sequence. Quantitative fluence rate response analysis showed that the mutant phytochrome A molecule produced by hy8-3 exhibited no detectable regulatory activity above that of the phyA-protein-deficient hy8-2 mutant. This result indicates that glycine-727, which is invariant in all sequenced phytochromes, has a function important to the regulatory activity of phytochrome A but not to photoperception.