Perry S E, Nichols K W, Fernandez D E
Department of Botany, University of Wisconsin-Madison 53706, USA.
Plant Cell. 1996 Nov;8(11):1977-89. doi: 10.1105/tpc.8.11.1977.
Little is known about regulatory factors that act during the earliest stages of plant embryogenesis. The MADS domain protein AGL15 (for AGAMOUS-like) is expressed preferentially during embryogenesis and accumulates during early seed development in monocotyledonous and dicotyledonous flowering plants. AGL15-specific antibodies and immunohistochemistry were used to demonstrate that AGL15 accumulates before fertilization in the cytoplasm in the cells of the egg apparatus and moves into the nucleus during early stages of development in the suspensor, embryo, and endosperms. Relatively high levels of AGL15 are present in the nuclei during embryo morphogenesis and until the seeds start to dry in Brassica, maize, and Arabidopsis. AGL15 is associated with the chromosomes during mitosis, and gel mobility shift assays were used to demonstrate that AGL15 binds DNA in a sequence-specific manner. To assess whether AGL15 is likely to play a role in specifying the seed or embryonic phase of development, AGL15 accumulation was examined in Arabidopsis mutants that prematurely exit embryogenesis. lec1-2 mutants show an embryo-specific loss of AGL15 at the transition stage, suggesting that AGL15 interacts with regulators in the leafy cotyledons pathway.
关于在植物胚胎发生最早阶段起作用的调控因子，人们了解甚少。MADS结构域蛋白AGL15（类AGAMOUS）在胚胎发生过程中优先表达，并在单子叶和双子叶开花植物的早期种子发育过程中积累。使用AGL15特异性抗体和免疫组织化学方法证明，AGL15在受精前在卵器细胞的细胞质中积累，并在胚柄、胚和胚乳发育的早期阶段进入细胞核。在甘蓝、玉米和拟南芥中，胚胎形态发生期间直至种子开始干燥时，细胞核中存在相对高水平的AGL15。有丝分裂期间AGL15与染色体相关，凝胶迁移率变动分析用于证明AGL15以序列特异性方式结合DNA。为了评估AGL15是否可能在确定种子或胚胎发育阶段中发挥作用，在过早退出胚胎发生的拟南芥突变体中检测了AGL15的积累情况。lec1-2突变体在过渡阶段显示出胚胎特异性的AGL15缺失，这表明AGL15与多子叶途径中的调控因子相互作用。
