A new role of the Arabidopsis SEPALLATA3 gene revealed by its constitutive expression
A new role of the Arabidopsis SEPALLATA3 gene revealed by its constitutive expression
复制标题
DOI：
10.1111/j.1365-313x.2005.02476.x
复制
发表时间：
2005-08-01
期刊：
影响因子：
7.2
通讯作者：
Pelaz, S
中科院分区：
文献类型：
--
作者：
Castillejo, C;Romera-Branchat, M;Pelaz, S
在拟南芥花发育过程中，一组同源异型基因起着核心作用，在指定不同的花器官的四个轮，萼片在最外的轮，花瓣，雄蕊，心皮在顺序内轮。目前花器官鉴定的模型包括SEPALLATA基因，该基因与A、B和C基因联合作用，用于萼片、花瓣、雄蕊和心皮的特化。根据这一新模型，花器官识别蛋白将形成不同的蛋白质复合物，以激活下游基因。我们表明，SEPALLATA蛋白的存在是激活AG下游基因SHATTERPROOF2所必需的，并且单独的SEPALLATA 4不能为复合物提供足够的SEPALLATA活性以发挥功能。我们的研究结果表明，花椰菜可能是负责花瓣发育的蛋白质复合物的一部分，并且在35S：：SEP 3植物中不存在APETALA 1的情况下，它是完全必需的。此外，使用组成型表达SEPALLATA 3的植物进行的遗传和分子实验揭示了SEPALLATA 3在激活其他B和C功能基因方面的新作用。我们从分子水平证明SEPALLATA3的异位表达足以异位激活APETALA3和AGAMOUS。值得注意的是，组成型表达SEPALLATA3和LEAFY的植物在花环境之外发育异位花瓣、心皮和胚珠。
During Arabidopsis flower development a set of homeotic genes plays a central role in specifying the distinct floral organs of the four whorls, sepals in the outermost whorl, and petals, stamens, and carpels in the sequentially inner whorls. The current model for the identity of the floral organs includes the SEPALLATA genes that act in combination with the A, B and C genes for the specification of sepals, petals, stamens and carpels. According to this new model, the floral organ identity proteins would form different complexes of proteins for the activation of the downstream genes. We show that the presence of SEPALLATA proteins is needed to activate the AG downstream gene SHATTERPROOF2, and that SEPALLATA4 alone does not provide with enough SEPALLATA activity for the complex to be functional. Our results suggest that CAULIFLOWER may be part of the protein complex responsible for petal development and that it is fully required in the absence of APETALA1 in 35S::SEP3 plants. In addition, genetic and molecular experiments using plants constitutively expressing SEPALLATA3 revealed a new role of SEPALLATA3 in activating other B and C function genes. We molecularly prove that the ectopic expression of SEPALLATA3 is sufficient to ectopically activate APETALA3 and AGAMOUS. Remarkably, plants that constitutively express both SEPALLATA3 and LEAFY developed ectopic petals, carpels and ovules outside of the floral context.