Krizek B A, Meyerowitz E M
Division of Biology, California Institute of Technology, Pasadena 91125, USA.
Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):4063-70. doi: 10.1073/pnas.93.9.4063.
The Arabidopsis MADS domain proteins AP1, AP3, PI, and AG specify floral organ identity. All of these proteins contain a MADS domain required for DNA binding and dimerization; a region termed L (linker between MADS domain and K domain), which plays an important role in dimerization specificity; the K domain, named for its similarity to the coiled-coil domain of keratin; and a C-terminal region of unknown function. To determine which regions of these proteins are responsible for their abilities to specify different organs, we have made a number of chimeric MADS box genes. The in vivo function of these chimeric genes was investigated by ectopic expression in transgenic Arabidopsis plants. The four proteins fall into two classes on the basis of regions responsible for their functional specificities. The L region and K domain define the functional specificities of AP3 and PI, while the MADS domain and L region define the functional specificities of AP1 and AG.
拟南芥MADS结构域蛋白AP1、AP3、PI和AG决定花器官的特征。所有这些蛋白都含有一个用于DNA结合和二聚化的MADS结构域；一个称为L（MADS结构域和K结构域之间的连接区）的区域，它在二聚化特异性中起重要作用；K结构域，因其与角蛋白的卷曲螺旋结构域相似而得名；以及一个功能未知的C末端区域。为了确定这些蛋白的哪些区域决定了它们指定不同器官的能力，我们构建了一些嵌合MADS盒基因。通过在转基因拟南芥植物中的异位表达研究了这些嵌合基因的体内功能。根据负责其功能特异性的区域，这四种蛋白分为两类。L区域和K结构域决定了AP3和PI的功能特异性，而MADS结构域和L区域决定了AP1和AG的功能特异性。
