Light Controls Protein Localization through Phytochrome-Mediated Alternative Promoter Selection
Light Controls Protein Localization through Phytochrome-Mediated Alternative Promoter Selection
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DOI：
10.1016/j.cell.2017.10.018
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发表时间：
2017-11-30
期刊：
影响因子：
64.5
通讯作者：
Matsushita, Tomonao
中科院分区：
文献类型：
--
作者：
Ushijima, Tomokazu;Hanada, Kousuke;Matsushita, Tomonao
另一种启动子的使用是一种蛋白质组扩展机制，允许从单个基因转录多个前mrna。这种机制对蛋白质组的影响以及它是否在正常的机体反应中被积极利用尚不清楚。我们发现植物光感受器光敏色素诱导拟南芥选择性启动子选择的全基因组变化。通过这一机制，产生了具有不同N末端的蛋白质同工异构体，这些异构体在定位上表现出光依赖性差异。例如，遮荫植物积累了甘油激酶（GLYK）的细胞质异构体，这是一种必需的光呼吸酶，以前被认为只存在于叶绿体中。胞质GLYK构成光呼吸旁路，减轻波动光诱导的光抑制。因此，光敏色素控制替代启动子的选择来调节蛋白质的定位，以响应不断变化的光照条件。这项研究表明，替代启动子的使用代表了真核生物中另一个普遍存在的基因表达调控层，有助于蛋白质组的多样化。
Alternative promoter usage is a proteome-expanding mechanism that allows multiple pre-mRNAs to be transcribed from a single gene. The impact of this mechanism on the proteome and whether it is positively exploited in normal organismal responses remain unclear. Wefound that the plant photoreceptor phytochrome induces genome-wide changes in alternative promoter selection in Arabidopsis thaliana. Through this mechanism, protein isoforms with different N termini are produced that display lightdependent differences in localization. For instance, shade-grown plants accumulate a cytoplasmic isoform of glycerate kinase (GLYK), an essential photorespiration enzyme that was previously thought to localize exclusively to the chloroplast. Cytoplasmic GLYK constitutes a photorespiratory bypass that alleviates fluctuating light-induced photoinhibition. Therefore, phytochrome controls alternative promoter selection to modulate protein localization in response to changing light conditions. This study suggests that alternative promoter usage represents anotherubiquitous layer of gene expression regulation in eukaryotes that contributes to diversification of the proteome.