Department of Botany, University of Illinois, Urbana, Illinois 61801.
Plant Physiol. 1983 Feb;71(2):215-22. doi: 10.1104/pp.71.2.215.
The pattern of protein synthesis in roots of 3-day-old maize seedlings (Zea mays L.) is rapidly and dramatically altered when the incubation temperature is raised from 25 to 40 degrees C. One-dimensional sodium dodecyl sulfate gels reveal that although synthesis of the proteins observed at 25 degrees C continues at 40 degrees C, a new set of ;heat shock proteins' (hsp) is induced within 20 minutes of the temperature transition. The hsp have molecular weights of 87, 85, 79, 78, 77, 72, 70, 27, 22, and 18 kilodaltons. The 10 hsp are visible on autoradiograms but not on stained gels, suggesting that the proteins do not accumulate to any great extent.The induction of the hsp is transitory. With prolonged high temperature treatment, the synthesis of hsp continues for 4 hours in excised roots and for 8 hours in the roots of intact seedlings before declining sharply. Coincident to the decline in synthesis of the 10 hsp is the gradual increase in intensity of three new polypeptides having molecular weights of 62, 49.5, and 19 kilodaltons. These proteins begin to appear about the time that synthesis of the other 10 hsp becomes maximal.Shifting the temperature back to 25 degrees C also causes a decline in synthesis of hsp, but this decline occurs more rapidly than that seen during prolonged heat shock. A decrease in hsp synthesis becomes apparent 2 hours after the roots are returned to 25 degrees C.Shifting the temperature from 25 to 45 degrees C results in a pattern of protein synthesis different from that observed after a shift to 40 degrees C. Normal protein synthesis continues, except four proteins, which are produced in small amounts at lower temperatures, show greatly enhanced synthesis at 45 degrees C. These proteins have apparent molecular weights of 83, 81, 68, and 65 kilodaltons. Also, the 10 hsp listed above are not synthesized. It is suggested that at least two distinct high-temperature responses are present in maize, which may reflect the metabolic changes generated at different elevated temperatures.
当培养温度从 25°C 升高到 40°C 时，三天大的玉米幼苗（Zea mays L.）根部的蛋白质合成模式会迅速而显著地改变。一维十二烷基硫酸钠凝胶显示，尽管在 25°C 下观察到的蛋白质合成在 40°C 下继续进行，但在温度转变后的 20 分钟内，会诱导一组新的“热休克蛋白”（hsp）。这些 hsp 的分子量分别为 87、85、79、78、77、72、70、27、22 和 18 千道尔顿。在放射自显影图上可以看到 10 个 hsp，但在染色凝胶上看不到，这表明这些蛋白质没有大量积累。hsp 的诱导是短暂的。在长时间的高温处理下，离体根中 hsp 的合成持续 4 小时，完整幼苗的根中持续 8 小时，然后急剧下降。与 10 个 hsp 合成的下降同时发生的是，分子量为 62、49.5 和 19 千道尔顿的三种新多肽的强度逐渐增加。这些蛋白质大约在其他 10 个 hsp 的合成达到最大值时开始出现。将温度调回 25°C 也会导致 hsp 合成的下降，但这种下降比长时间热休克时更快。将温度从 25°C 调回 2 小时后，hsp 合成的减少就变得明显了。将温度从 25°C 升高到 45°C 会导致与升高到 40°C 后观察到的蛋白质合成模式不同。除了四种在较低温度下少量产生的蛋白质外，正常蛋白质合成继续进行，这些蛋白质在 45°C 时的合成量大大增加。这些蛋白质的表观分子量分别为 83、81、68 和 65 千道尔顿。此外，上面列出的 10 个 hsp 也没有合成。这表明玉米中至少存在两种不同的高温反应，这可能反映了在不同升高温度下产生的代谢变化。
