青花菜AGL18及HDA9与开花信号整合子互作研究

为阐明青花菜（Brassica oleracea var. italica）开花抑制因子AGL18、HDA9与开花信号整合子AGL24以及SOC1之间的互作机制，分别克隆了青花菜AGL18和HDA9基因，它们与十字花科甘蓝、芜菁等同源性较高。AGL18编码258个氨基酸，其蛋白属于MIKC型。HDA9编码426个氨基酸，其蛋白属于HDAC亚家族。酵母双杂交及GST pull-down结果表明：AGL18与HDA9无蛋白互作，说明它们彼此间不能直接协同作用。AGL18与开花促进因子AGL19也无互作，暗示它们以相对独立的方式抑制或促进开花。HDA9与AGL24、SOC1均不能蛋白互作，然而AGL18能与AGL24蛋白互作却不能与SOC1互作，AGL24能与SOC1互作。由此表明AGL18可通过AGL24间接作用于SOC1。

Protein Interactions of Flowering Inhibitors AGL18 and HDA9 with Integrator Factors in Brassica oleracea var. italica

To elucidate the protein interaction mechanisms of flowering inhibition factors AGL18 and HDA9 with flowering integrators AGL24 and SOC1，AGL18 and HDA9 genes were cloned from Brassica oleracea var. italica. Sequence analysis showed that they were both similar to Brassica oleracea var. oleracea and Brassica rapa. AGL18 was a MIKC-type protein with 258 amino acids，while HDA9 belonged to HDAC family，encoding 426 amino acids. Furthermore，yeast two-hybrid and GST pull-down assays were conducted to test the protein interactions and the results were as follows：AGL18 could not interact with HDA9，suggesting that there was no direct synergy between AGL18 and HDA9. And flowering inhibition factor AGL18 did not interact with flowering promoting factor AGL19，inferring that they inhibited or promoted flowering in a mutually independent way. HDA9 could not interact with AGL24 and SOC1，while AGL18 interacted with AGL24 not SOC1. Additionally，AGL24 interacted with SOC1. The results indicated that AGL18 could indirectly interact with SOC1 through AGL24.