Tominaga-Wada Rumi, Wada Takuji
Graduate School of Biosphere Sciences, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan
Graduate School of Biosphere Sciences, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan.
Development. 2017 Jul 1;144(13):2375-2380. doi: 10.1242/dev.149542.
The () gene encodes a R3-type MYB transcription factor that promotes differentiation of root hair cells in Here, we have compared the functions of five -homologous genes for epidermal cell differentiation using promoter-driven transgenic plants. Our results show that TRIPTYCHON (TRY) and ENHANCER OF TRY AND CPC2 (ETC2) were less effective in root hair cell differentiation and were unstable in root epidermal cells when compared with CPC, ETC1 or CPC LIKE MYB3 (CPL3). The deletion of the extended C-terminal domain of TRY and ETC2 enhanced protein stability and conferred the ability to induce root hair cell differentiation on them. Treatment with MG132, a proteasome inhibitor, also led to the accumulation of TRY, indicating that TRY proteolysis is mediated by the proteasome-dependent pathway. Our results indicate that the CPC family includes relatively stable (CPC, ETC1 and CPL3) and unstable (TRY and ETC2) proteins that might be degraded by the proteasome. Our findings provide new insights into the regulatory mechanism of CPC family proteins that mediate root hair cell differentiation and should be useful in understanding epidermal development.
（）基因编码一种R3型MYB转录因子，该因子促进根毛细胞的分化。在此，我们使用启动子驱动的转基因植物比较了五个同源基因在表皮细胞分化中的功能。我们的结果表明，与CPC、ETC1或CPC类MYB3（CPL3）相比，三联体（TRY）和TRY与CPC2增强子（ETC2）在根毛细胞分化中效果较差，且在根表皮细胞中不稳定。删除TRY和ETC2的延伸C末端结构域可增强蛋白质稳定性，并赋予它们诱导根毛细胞分化的能力。用蛋白酶体抑制剂MG132处理也导致TRY的积累，表明TRY的蛋白水解是由蛋白酶体依赖性途径介导的。我们的结果表明，CPC家族包括可能被蛋白酶体降解的相对稳定的（CPC、ETC1和CPL3）和不稳定的（TRY和ETC2）蛋白质。我们的发现为介导根毛细胞分化的CPC家族蛋白的调控机制提供了新的见解，并且对于理解表皮发育应该是有用的。
