Biotechnology Research Center, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
Biotechnology Research Center, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
J Exp Bot. 2014 Oct;65(19):5589-600. doi: 10.1093/jxb/eru267. Epub 2014 Jul 8.
Nitrogen is one of the primary macronutrients of plants, and nitrate is the most abundant inorganic form of nitrogen in soils. Plants take up nitrate in soils and utilize it both for nitrogen assimilation and as a signalling molecule. Thus, an essential role for nitrate in plants is triggering changes in gene expression patterns, including immediate induction of the expression of genes involved in nitrate transport and assimilation, as well as several transcription factor genes and genes related to carbon metabolism and cytokinin biosynthesis and response. Significant progress has been made in recent years towards understanding the molecular mechanisms underlying nitrate-regulated gene expression in higher plants; a new stage in our understanding of this process is emerging. A key finding is the identification of NIN-like proteins (NLPs) as transcription factors governing nitrate-inducible gene expression. NLPs bind to nitrate-responsive DNA elements (NREs) located at nitrate-inducible gene loci and activate their NRE-dependent expression. Importantly, post-translational regulation of NLP activity by nitrate signalling was strongly suggested to be a vital process in NLP-mediated transcriptional activation and subsequent nitrate responses. We present an overview of the current knowledge of the molecular mechanisms underlying nitrate-regulated gene expression in higher plants.
氮是植物的主要大量营养素之一，硝酸盐是土壤中最丰富的无机氮形式。植物从土壤中吸收硝酸盐，将其用于氮同化和作为信号分子。因此，硝酸盐在植物中的一个重要作用是触发基因表达模式的变化，包括立即诱导参与硝酸盐运输和同化的基因的表达，以及几个转录因子基因和与碳代谢以及细胞分裂素生物合成和反应相关的基因。近年来，在理解高等植物中硝酸盐调节基因表达的分子机制方面取得了重大进展；我们对这一过程的理解正在进入一个新阶段。一个关键的发现是鉴定出作为调控硝酸盐诱导基因表达的转录因子的类似 NIN 蛋白 (NLPs)。NLPs 与位于硝酸盐诱导基因座的硝酸盐反应性 DNA 元件 (NREs) 结合，并激活它们的 NRE 依赖性表达。重要的是，硝酸盐信号对 NLP 活性的翻译后调节被强烈认为是 NLP 介导的转录激活和随后的硝酸盐反应中的一个重要过程。我们概述了目前对高等植物中硝酸盐调节基因表达的分子机制的认识。
