del Pozo Juan C, Dharmasiri Sunethra, Hellmann Hanjo, Walker Loni, Gray William M, Estelle Mark
Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Texas 78712, USA.
Plant Cell. 2002 Feb;14(2):421-33. doi: 10.1105/tpc.010282.
Mutations in the AXR1 gene result in a reduction in auxin response and diverse defects in auxin-regulated growth and development. In a previous study, we showed that AXR1 forms a heterodimer with the ECR1 protein. This enzyme activates the ubiquitin-related protein RUB1 in vitro. Furthermore, we showed that the Skp1-Cul1/Cdc53-F-box (SCF) subunit AtCUL1 is modified by RUB1 in vivo. In this report, we demonstrate that the formation of RUB-AtCUL1 is dependent on AXR1 and ECR1 in vivo. The expression of AXR1 and ECR1 is restricted to zones of active cell division and cell elongation, consistent with their role in growth regulation. These results provide strong support for a model in which RUB conjugation of AtCUL1 affects the function of SCF E3s that are required for auxin response.
AXR1基因的突变导致生长素反应降低以及生长素调节的生长和发育出现多种缺陷。在之前的一项研究中,我们表明AXR1与ECR1蛋白形成异二聚体。这种酶在体外激活泛素相关蛋白RUB1。此外,我们还表明Skp1-Cul1/Cdc53-F-box(SCF)亚基AtCUL1在体内被RUB1修饰。在本报告中,我们证明RUB-AtCUL1的形成在体内依赖于AXR1和ECR1。AXR1和ECR1的表达局限于活跃的细胞分裂和细胞伸长区域,这与其在生长调节中的作用一致。这些结果为一个模型提供了有力支持,该模型认为AtCUL1的RUB缀合影响生长素反应所需的SCF E3泛素连接酶的功能。