School of Agricultural, Biological, and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori, Japan.
Plant Sci. 2011 Oct;181(4):421-7. doi: 10.1016/j.plantsci.2011.07.001. Epub 2011 Jul 19.
We investigated the transcript levels of 13 proteasome subunit genes, the protein levels of proteasomes, and the activities of the 26S proteasome in ANAC078-overexpressing Arabidopsis plants (Ox-ANAC078) and knockout ANAC078 (KO-ANAC078) mutants. The transcript levels and the protein levels of proteasomes were increased in the Ox-ANAC078 plants compared with the wild-type plants and KO-ANAC078 mutants under normal conditions and high-light (HL) stress. Although the activities of the 26S proteasome were decreased in all the plants under HL stress, they were higher in the Ox-ANAC078 plants than wild-type plants and KO-ANAC078 mutants under normal conditions and HL stress. These findings suggest that ANAC078 regulates the levels of proteasomes. To explore the function of the increased levels of proteasomes to HL stress, we assessed the tolerance to HL stress of the Ox-ANAC078 plants and KO-ANAC078 mutants. The photosystem II activities of Ox-ANAC078 remained high compared with those of the wild-type plants and KO-ANAC078 mutants under HL stress, suggesting that ANAC078 may play an important role in the response and adaptation to HL stress.
我们研究了过表达拟南芥 ANAC078 （Ox-ANAC078）和敲除 ANAC078 （KO-ANAC078）突变体中 13 种蛋白酶体亚基基因的转录水平、蛋白酶体的蛋白质水平以及 26S 蛋白酶体的活性。与野生型植物和 KO-ANAC078 突变体相比，在正常条件和高光（HL）胁迫下，Ox-ANAC078 植物中蛋白酶体的转录水平和蛋白质水平均升高。尽管在 HL 胁迫下所有植物的 26S 蛋白酶体活性均降低，但在正常条件和 HL 胁迫下，Ox-ANAC078 植物中的活性均高于野生型植物和 KO-ANAC078 突变体。这些发现表明 ANAC078 调节蛋白酶体的水平。为了探讨蛋白酶体水平升高对 HL 胁迫的功能，我们评估了 Ox-ANAC078 植物和 KO-ANAC078 突变体对 HL 胁迫的耐受性。与野生型植物和 KO-ANAC078 突变体相比，Ox-ANAC078 的光系统 II 活性在 HL 胁迫下仍保持较高水平，表明 ANAC078 可能在响应和适应 HL 胁迫中发挥重要作用。
