MUTATIONS IN THE NPH1 LOCUS OF ARABIDOPSIS DISRUPT THE PERCEPTION OF PHOTOTROPIC STIMULI
MUTATIONS IN THE NPH1 LOCUS OF ARABIDOPSIS DISRUPT THE PERCEPTION OF PHOTOTROPIC STIMULI
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DOI：
10.1105/tpc.7.4.473
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发表时间：
1995-04-01
期刊：
影响因子：
11.6
通讯作者：
BRIGGS, WR
中科院分区：
文献类型：
--
作者：
LISCUM, E;BRIGGS, WR
光致反应是高等植物幼苗建立的一个重要组成部分，因为它定位于最大限度地捕获光合作用的幼苗。尽管它们具有明显的重要性，但人们对诱导光致弯曲的光信号的感知和转导机制知之甚少。在这里，我们报告了八个缺乏或严重削弱了光致反应的拟南芥突变体的分离。这些NPH(非光性下胚轴)突变体包括四个遗传位点：nph1、nph2、nph3和nph4。对nph1等位基因序列的生理生化分析表明，NPH1基因座可能编码一种能吸收UV-A、蓝光和绿光的双色或多色全蛋白光感受器的脱辅基蛋白，该光感受器调节拟南芥的所有光致反应。看来NPH1蛋白很可能是一种120kD的质膜相关磷酸蛋白，因为所有的nph1突变都对该蛋白的丰度产生了负面影响。此外，推测的NPH1光感受器蛋白在遗传和生化上与HY4蛋白不同，HY4蛋白很可能是蓝光介导的下胚轴生长抑制的光感受器。此外，NPH1和HY4蛋白在功能上不是多余的，因为这两个基因的突变只影响一个生理反应，而不影响另一个，从而为幼苗的正常生长和发育需要不止一个蓝光感受器的假说提供了强有力的支持。
The phototropic response is an important component of seedling establishment in higher plants because it orients the young seedlings for maximal photosynthetic light capture. Despite their obvious importance, little is known about the mechanisms underlying the perception and transduction of the light signals that induce phototropic curvatures. Here, we report the isolation of eight mutants of Arabidopsis that lack or have severely impaired phototropic responses. These nph (for nonphototropic hypocotyl) mutants comprise four genetic loci: nph1, nph2, nph3, and nph4. Physiological and biochemical characterization of the nph1 allele series indicated that the NPH1 locus may encode the apoprotein for a dual-chromophoric or multichromophoric holoprotein photoreceptor capable of absorbing UV-A, blue, and green light and that this photoreceptor regulates all the phototropic responses of Arabidopsis. It appears that the NPH1 protein is most likely a 120-kD plasma membrane-associated phosphoprotein because all of the nph1 mutations negatively affected the abundance of this protein. In addition, the putative NPH1 photoreceptor protein is genetically and biochemically distinct from the HY4 protein, which most likely acts as a photoreceptor for blue light-mediated hypocotyl growth inhibition. Furthermore, the NPH1 and HY4 proteins are not functionally redundant because mutations in either gene alone affect only one physiological response but not the other, thus providing strong support for the hypothesis that more than one blue light photoreceptor is required for the normal growth and development of a seedling.