Functional Characterization of the Arabidopsis thaliana BTB/POZ-MATH domain protein family

进化上保守的BTB/POZ和MATH基序可以在昆虫、鱼类、哺乳动物和植物等多种生物中发现。含有这两个基序的蛋白质已被证明参与转录调控和减数分裂过程。此外，最近的研究结果揭示了BTB/POZ-MATH-蛋白和Cullin之间的联系，Cullin含有在泛素蛋白酶体途径中有活性的E3泛素连接酶。拟南芥基因组编码6个BTB/POZ-MATH蛋白，均与哺乳动物和C.优雅到目前为止，还不知道该家族在植物中的功能和生物学作用。我们已经克隆了三个有代表性的成员，并可以证明所有的相互作用与AtCUL 3蛋白质，以及同源和异源二聚化与对方。相互作用取决于BTB结构域，不需要MATH基序。因此，在该项目中，将详细分析所有六个BTB/POZ-MATH基因的详细表达模式、亚细胞蛋白定位和无效突变体的表型。该项目将鉴定新的相互作用蛋白，验证该家族与泛素蛋白酶体通路的功能连接，并将每个单独的BTB/POZ-MATH蛋白置于其活跃的调控网络中。

The evolutionary conserved BTB/POZ and MATH-motifs can be found in various organisms ranging from insects, fish, mammals and plants. Proteins containing both motifs have been demonstrated to participate in transcriptional regulation and meiotic processes. In addition, recent findings revealed the connection between BTB/POZ-MATH-proteins and Cullin containing E3 ubiquitin ligases that are active in the ubiquitin proteasome pathway. The Arabidopsis genome encodes for six BTB/POZ-MATH proteins all related to speckle-type POZ proteins from mammals and C. elegans. So far nothing is known about the function and biological roles of this family in plants. We have cloned three representative members and can demonstrate interaction of all with AtCUL3 proteins as well as homo- and heterodimerization with each other. Interactions depend on the BTB-domain and do not require the MATH-motif. Thus, within the project detailed expression patterns of all six BTB/POZ-MATH genes, subcellular protein localization and phenotypes of null mutants will be analyzed in detail. The project will identify new interacting proteins, verify functional connections of the family to the ubiquitin proteasome pathway, and place each individual BTB/POZ-MATH protein into the regulatory networks in which it is active.