Smith Harley M S, Boschke Ilja, Hake Sarah
Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
Proc Natl Acad Sci U S A. 2002 Jul 9;99(14):9579-84. doi: 10.1073/pnas.092271599. Epub 2002 Jul 1.
Understanding molecular mechanisms that control cell fate in the shoot apical meristem is a fundamental question in plant development. Genetic and molecular studies demonstrate that maize KNOTTED1 (KN1) of the TALE (3-aa acid loop extension) class of homeodomain (HD) proteins is involved in shoot apical meristem function. We show that KN1 interacts with knotted interacting protein (KIP), a BEL1-like TALE HD protein. Interaction between KN1 and KIP is mediated by conserved domains in the N termini of both proteins. The KN1 DNA-binding sequence, TGACAG(G/C)T, was biochemically identified, and in vitro DNA-binding assays show that individually KN1 and the HD of KIP bind specifically to this motif with low affinity. The KN1-KIP complex, however, binds specifically to this DNA-binding motif with high affinity, indicating that the association of KN1 and KIP may function in transcriptional regulation.
了解控制茎尖分生组织细胞命运的分子机制是植物发育中的一个基本问题。遗传和分子研究表明，同源异型域（HD）蛋白的TALE（三氨基酸环延伸）类的玉米KNOTTED1（KN1）参与茎尖分生组织功能。我们发现KN1与一种类BEL1的TALE HD蛋白——结相互作用蛋白（KIP）相互作用。KN1和KIP之间的相互作用由两种蛋白质N端的保守结构域介导。通过生化方法鉴定了KN1的DNA结合序列TGACAG(G/C)T，体外DNA结合试验表明，单独的KN1和KIP的HD以低亲和力特异性结合该基序。然而，KN1-KIP复合物以高亲和力特异性结合该DNA结合基序，表明KN1和KIP的结合可能在转录调控中起作用。
