KNOX lost the OX:: The Arabidopsis KNATM gene defines a novel class of KNOX transcriptional regulators missing the homeodomain
KNOX lost the OX:: The Arabidopsis KNATM gene defines a novel class of KNOX transcriptional regulators missing the homeodomain
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DOI：
10.1105/tpc.108.058495
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发表时间：
2008-04-01
期刊：
影响因子：
11.6
通讯作者：
Hake, Sarah
中科院分区：
文献类型：
--
作者：
Magnani, Enrico;Hake, Sarah
三个氨基酸环延伸(TALE)同源结构域转录调控因子在植物和动物的发育过程中发挥着核心作用。植物KNOTTED1-like Homeobox(KNOX)蛋白和动物髓样生态致病病毒整合位点(MEIS)蛋白共享一个同源结构域和一个MEINOX(Meis-Knox)结构域，这表明祖先的MEINOX-TALL蛋白早于植物与真菌和动物的分化。在这项研究中，我们鉴定和鉴定了拟南芥KNATM基因，该基因编码一个MEINOX结构域，而不是一个同源结构域。对KNOX家族的系统发育分析将KNAM归入一个新的纲，并显示出双子叶植物的保守性。我们证明KNatM通过MEINOX结构域选择性地与拟南芥贝尔故事蛋白相互作用。已知同源结构域是诺克斯与诺克斯相互作用所必需的。相反，KNAM通过酸性卷曲结构域与KNOX蛋白BREVIPEDICELLUS特异性二聚。KNAM在器官原基的近侧区域和成熟器官的边界表达；根据遗传分析，KNAM在叶片近端-远端模式中具有功能。体内结构域分析突出了KNAM功能区，并揭示了作为转录调节因子的作用。综上所述，我们的数据揭示了KNOX二聚化和转录调控的同源结构域无关的机制。
Three amino acid loop extension ( TALE) homeodomain transcriptional regulators play a central role in plant and animal developmental programs. Plant KNOTTED1-like homeobox (KNOX) and animal Myeloid ecotropic viral integration site (MEIS) proteins share a TALE homeodomain and a MEINOX (MEIS-KNOX) domain, suggesting that an ancestral MEINOX-TALE protein predates the divergence of plants from fungi and animals. In this study, we identify and characterize the Arabidopsis thaliana KNATM gene, which encodes a MEINOX domain but not a homeodomain. Phylogenetic analysis of the KNOX family places KNATM in a new class and shows conservation in dicotyledons. We demonstrate that KNATM selectively interacts with Arabidopsis BELL TALE proteins through the MEINOX domain. The homeodomain is known to be necessary for KNOX KNOX interaction. On the contrary, KNATM specifically dimerizes with the KNOX protein BREVIPEDICELLUS through an acidic coiled-coil domain. KNATM is expressed in proximal-lateral domains of organ primordia and at the boundary of mature organs; in accordance, genetic analyses identify a function for KNATM in leaf proximal-distal patterning. In vivo domain analyses highlighted KNATM functional regions and revealed a role as transcriptional regulator. Taken together, our data reveal a homeodomain-independent mechanism of KNOX dimerization and transcriptional regulation.