Mallappa Chandrashekara, Yadav Vandana, Negi Prem, Chattopadhyay Sudip
National Centre for Plant Genome Research, Laboratory 101, Aruna Asaf Ali Marg, New Delhi 110067, India.
National Centre for Plant Genome Research, Laboratory 101, Aruna Asaf Ali Marg, New Delhi 110067, India.
J Biol Chem. 2006 Aug 4;281(31):22190-22199. doi: 10.1074/jbc.M601172200. Epub 2006 Apr 25.
Several transcriptional regulators have been identified and demonstrated to play either positive or negative regulatory roles in seedling development. However, the regulatory coordination between hypocotyl elongation and cotyledon expansion during early seedling development in plants remains unknown. We report the identification of a Z-box binding factor (ZBF2) and its functional characterization in cryptochrome-mediated blue light signaling. ZBF2 encodes a G-box binding factor (GBF1), which is a basic leucine zipper transcription factor. Our DNA-protein interaction studies reveal that ZBF2/GBF1 also interacts with the Z-box light-responsive element of light-regulated promoters. Genetic analyses of gbf1 mutants and overexpression studies suggest that GBF1 acts as a repressor of blue light-mediated inhibition in hypocotyl elongation, however, it acts as a positive regulator of cotyledon expansion during photomorphogenic growth. Furthermore, whereas GBF1 acts as a positive regulator of lateral root formation, it differentially regulates the expression of light-inducible genes. Taken together, these results demonstrate that GBF1 is a unique transcriptional regulator of photomorphogenesis in blue light.
已经鉴定出几种转录调节因子，并证明它们在幼苗发育中发挥正向或负向调节作用。然而，植物幼苗早期发育过程中下胚轴伸长和子叶扩展之间的调节协调仍不清楚。我们报告了一种Z盒结合因子（ZBF2）的鉴定及其在隐花色素介导的蓝光信号传导中的功能表征。ZBF2编码一种G盒结合因子（GBF1），它是一种碱性亮氨酸拉链转录因子。我们的DNA-蛋白质相互作用研究表明，ZBF2/GBF1也与光调节启动子的Z盒光响应元件相互作用。对gbf1突变体的遗传分析和过表达研究表明，GBF1在蓝光介导的下胚轴伸长抑制中起抑制作用，然而，在光形态建成生长过程中，它作为子叶扩展的正向调节因子。此外，虽然GBF1作为侧根形成的正向调节因子，但它差异调节光诱导基因的表达。综上所述，这些结果表明GBF1是蓝光下光形态建成的独特转录调节因子。
