Elements regulatingAGAMOUSexpression are conserved betweenArabidopsis thaliana,Brassica napus, andLinum usitatissimum

Abstract

To investigate the functional conservation of cis regulatory elements controlling AGAMOUS (AG) expression, we placed the promoter region of AG from Arabidopsis thaliana into a close relative, Brassica napus, and a distantly related species, Linum usitatissimum, and analyzed the subsequent expression patterns in each species. Spatially, the expression patterns in all three species were marginally similar, in that expression was confined primarily to the reproductive organs and nectarium. Within organs however, tissue-specific expression patterns were not conserved between species. Unlike Arabidopsis, the transgenic AG cis elements did not express in the ovules of B. napus and L. usitatissimum. Temporally, the pattern of AG cis-element expression in B. napus was identical to that of Arabidopsis during early development; however, the AG cis elements did not express at all during early flower development in L. usitatissimum. These results suggest that although regulatory factors controlling the generalized local expression of AG have been conserved between these species, those controlling temporal and tissue-specific expression have not.Key words: AGAMOUS, cis elements, regulation, Arabidopsis, Brassica napus, Linum usitatissimum.

Isolation and Analysis of <I>AGAMOUS</I> Homologous Gene and Its Pro-moter from <I>Vicia sativa</I> L.

“…AG 基因在植物雌蕊和果实发育控制过程中居 核心位置, 在拟南芥中其表达受 LFY、AP2 及 ANT 等基因的调控 [14][15] , 并与 WUS 形成反馈环通过控制 花器官顶端干细胞的命运决定了花器官轮数的多 少。在拟南芥中, AG 基因缺失或表达水平下调导致 器官轮数增多等现象 [16] 。这表明 AG 基因可能参与 调控多个基因的表达。Folter 等 [17] 通过酵母双杂交 实验证实了这一观点, 发现 AG 基因与 SHP、 STK 和 SEP 等功能基因在蛋白质水平存在相互作用。然而 至今尚未发现 AG 的直接靶基因。 AG 基因在高等植物中广泛存在, 目前在豆科 植物蒺藜苜蓿和豌豆中均已发现 [18] 。徐雷等 [19] 功能可能与 PsAG 类似。 AG 基因上游启动子元件在近缘物种间的调控 特征并不保守, 拟南芥 AG 基因启动子并不能有效 启 动 油 菜 (Brassica napus) 和 亚 麻 (Linum usitatissimum)的瞬时表达 [20] 。 然而, 具有 WUS 和 LFY 基因 调控位点表达的第二内含子区域的调控元件在近缘 种间表现出保守特征, 桃(Prunus perscia)的 PpMADS4 基因第二内含子却可以指导 GUS 在拟南芥第三、四 轮花器官的表达 [21] 。Hong 等 [12] 利用报告基因、系统 发生印迹法(phylogenetic footprinting)和系统发生渐…”