THE CUCUMBER LONG HYPOCOTYL MUTANT LACKS A LIGHT-STABLE PHYB-LIKE PHYTOCHROME
THE CUCUMBER LONG HYPOCOTYL MUTANT LACKS A LIGHT-STABLE PHYB-LIKE PHYTOCHROME
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DOI：
10.1105/tpc.4.3.241
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发表时间：
1992-03-01
期刊：
影响因子：
11.6
通讯作者：
FURUYA, M
中科院分区：
文献类型：
--
作者：
LOPEZJUEZ, E;NAGATANI, A;FURUYA, M
与从烟草组织的文库中分离的光敏色素B（phyB）基因同源的新的cDNA序列已被用于大肠杆菌表达系统以产生抗光敏色素B（抗PHYB）多肽特异性单克隆抗体。这些抗体的特异性已经通过针对纯化的豌豆光不稳定的1型和光稳定的2型光敏色素的交叉反应性进行了测试，其中一些抗体与2型光敏色素反应，而不与1型光敏色素反应。一种这样的抗体，单克隆mAT 1，已被用来分析存在于黄瓜的光形态发生长下胚轴（LH）突变体中的光敏色素分子种类。结果表明，突变体含有野生型水平的光不稳定的1型光敏色素多肽（PHYA），其具有约120 kD的表观分子量，但在野生型幼苗中显示< 1%（检测限）的mAT 1识别的光稳定多肽。这种蛋白质，在lh突变体中检测不到，具有光稳定的2型光敏色素的性质，具有116至117 kD的表观分子量，并在连续低通量率红光下保持恒定水平。因此，我们得出结论，lh突变体缺乏至少一个2型光敏色素样多肽，最有可能是phyB基因产物。缺乏这种蛋白质和缺乏或缺乏光稳定的光敏色素物种在此突变体的生理反应之间的相关性，有助于确定光敏色素基因家族内的不同亚科的产品所发挥的生理作用。
A novel cDNA sequence homologous to a phytochrome B (phyB) gene that was isolated in a library from tobacco tissue has been used in an Escherichia coli expression system to raise anti-phytochrome B (anti-PHYB) polypeptide-specific monoclonal antibodies. The specificity of these antibodies has been tested by cross-reactivity against purified pea light-labile type 1 and light-stable type 2 phytochromes, with some antibodies reacting with the type 2 and none with the type 1 phytochromes. One such antibody, monoclonal mAT1, has been employed to analyze the phytochrome molecular species present in a photomorphogenic long hypocotyl (lh) mutant of cucumber. The results indicated that the mutant contains wild-type levels of the light-labile type 1 phytochrome polypeptide (PHYA), which has an apparent molecular mass of approximately 120 kD, but shows < 1% (detection limit) of a light-stable polypeptide recognized by mAT1 in wild-type seedlings. This protein, not detectable in the lh mutant, has the properties of light-stable type 2 phytochrome, has an apparent molecular mass of 116 to 117 kD, and remains at constant levels under continuous low-fluence-rate red light. Therefore, we conclude that the lh mutant lacks at least one type 2 phytochrome-like polypeptide, most probably a phyB gene product. The correlation between the lack of this protein and the deficiency or absence of physiological responses to a light-stable phytochrome species in this mutant helps to identify the physiological roles played by the products of different subfamilies within the phytochrome gene family.