Activation tagging of a gene for a protein with novel class of CCT-domain activates expression of a subset of sugar-inducible genes in Arabidopsis thaliana
Activation tagging of a gene for a protein with novel class of CCT-domain activates expression of a subset of sugar-inducible genes in Arabidopsis thaliana
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DOI：
10.1111/j.1365-313x.2005.02439.x
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发表时间：
2005-07-01
期刊：
影响因子：
7.2
通讯作者：
Nakamura, K
中科院分区：
文献类型：
--
作者：
Masaki, T;Tsukagoshi, H;Nakamura, K
在目前的研究中，我们利用拟南芥系sGsL检测了糖诱导基因的表达，该系携带荧光素酶（LUC）和β -葡糖醛酸酶（GUS）报告基因，在源自甘薯孢子素基因（Spo(min)）的210 bp启动子的控制下。我们分离了该细胞系的增强子激活标记突变体，该突变体在非诱导低糖条件下表现出LUC和GUS的高水平表达。靠近增强子的(S) bar po(min): (L) bar UC2 （ASML2）基因的(A) bar下激活子编码一种属于以前未被鉴定的CCT （CONSTANS, CONSTANS-like, TOC1）结构域蛋白。ASML2 cDNA在sGsL细胞系中的过表达不仅导致LUC和GUS报告基因的表达增强，还导致了几种内源性糖诱导基因的表达增强，包括At β - amy、ApL3和VSP2。在原生质体中，35S::ASML2与Spo(min)::LUC或At β - amy::LUC报告基因的瞬时共表达分别导致LUC表达的转激活约2.4倍或5.6倍。ASML2在生殖器官中表达量较高，在幼苗中的表达在糖的作用下略有增强，但在脱落酸的作用下没有增强。这些结果表明，ASML2作为转录激活因子起作用，并调节至少一部分糖诱导基因的表达。
In the current studies, we examined sugar-inducible gene expression using the Arabidopsis thaliana line sGsL, which carries luciferase (LUC) and beta-glucuronidase (GUS) reporter genes under the control of a 210-bp promoter derived from the sweet potato sporamin gene (Spo(min)). We isolated an enhancer activation-tagged mutant of this line that showed high-level expression of LUC and GUS under non-inducing low-sugar conditions. The (A) under bar ctivator of (S) under bar po(min)::(L) under bar UC2 (ASML2) gene located close to the enhancer encodes a protein belonging to a previously uncharacterized class of CCT (CONSTANS, CONSTANS-like, TOC1) domain proteins. Overexpression of ASML2 cDNA in the sGsL line resulted in enhanced expression of not only LUC and GUS reporters but also several endogenous sugar-inducible genes, including At beta-Amy, ApL3, and VSP2. Transient co-expression of 35S::ASML2 with the Spo(min)::LUC or At beta-Amy::LUC reporter in protoplasts resulted in an approximately 2.4 or 5.6-fold transactivation of LUC expression, respectively. Expression of ASML2 was high in reproductive organs, and expression in seedlings was slightly enhanced by sugars, but not by abscisic acid. These results suggest that ASML2 functions as a transcriptional activator and regulates the expression of at least a subset of sugar-inducible genes.