Institut für Biologie II, Universität Freiburg, Schänzlestrasse 1, D-7800, Freiburg i. Br., Germany.
Planta. 1987 Jul;171(3):332-8. doi: 10.1007/BF00398678.
The intracellular localisation of phytochrome and ubiquitin in irradiated oat coleoptiles was analysed by electron microscopy. We applied indirect immunolabeling with polyclonal antibodies against phytochrome from etiolated oat seedlings or polyclonal antibodies against ubiquitin from rabbit reticulocytes, together with a goldcoupled second antibody, on serial ultrathin sections of resin-embedded material. Immediately after a 5-min pulse of red light-converting phytochrome from the red-absorbing (Pr) to the far-redabsorbing (Pfr) form-the label for phytochrome was found to be sequestered in electron-dense areas. For up to 2 h after irradiation, the size of these areas increased with increasing dark periods. The ubiquitin label was found in the same electrondense areas only after a dark period of 30 min. A 5 min pulse of far-red light, which reverts Pfr to Pr, given immediately after the red light did not cause the electron-dense structures to disappear; moreover, they contained the phytochrome label immediately after the far-red pulse. In contrast, after the reverting far-red light pulse, ubiquitin could only be visualised in the electron-dense areas after prolonged dark periods (i.e. 60 min). The relevance of these data to light-induced phytochrome pelletability and to the destruction of both Pr and Pfr is discussed.
用电子显微镜分析了经辐照的燕麦中胚轴细胞内的光敏色素和泛素的细胞内定位。我们将针对来自黄化燕麦幼苗的光敏色素的多克隆抗体或针对来自兔网织红细胞的泛素的多克隆抗体与金偶联的第二抗体一起应用于树脂包埋材料的连续超薄切片上进行间接免疫标记。在 5 分钟的红光脉冲（将光敏色素从红光吸收形式（Pr）转化为远红光吸收形式（Pfr））之后，立即发现光敏色素的标记被隔离在电子致密区域中。在辐照后长达 2 小时内，这些区域的大小随着暗期的延长而增加。仅在暗期为 30 分钟后，泛素标记才出现在相同的电子致密区域中。在红光之后立即给予的 5 分钟远红光脉冲将 Pfr 恢复为 Pr，但不会导致电子致密结构消失；此外，它们在远红光脉冲后立即包含光敏色素标记。相比之下，在恢复远红光脉冲后，只有在延长的暗期（即 60 分钟）后，才能在电子致密区域中观察到泛素。讨论了这些数据与光诱导的光敏色素沉淀能力以及 Pr 和 Pfr 的破坏之间的相关性。
