College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Int J Mol Sci. 2020 Sep 14;21(18):6731. doi: 10.3390/ijms21186731.
We previously reported that the virulence protein VirD5 possesses transcriptional activation activity, binds to a specific DNA element D5RE, and is required for -mediated stable transformation, but not for transient transformation. However, direct evidence for a role of VirD5 in plant transcriptional regulation has been lacking. In this study, we found that the Arabidopsis gene (coding for VirD5 response F-box protein, ) is regulated by VirD5. has two alternative transcripts of 930 bp and 1594 bp that encode F-box proteins of 309 and 449 amino acids, designated as D5RF.1 and D5RF.2, respectively. D5RF.2 has a N-terminal extension of 140 amino acids compared to D5RF.1, and both of them are located in the plant cell nucleus. The promoter of the contains two D5RE elements and can be activated by VirD5. The expression of D5RF is downregulated when the host plant is infected with deleted . Similar to VirD5, D5RF also affects the stable but not transient transformation efficiency of . Some pathogen-responsive genes are downregulated in the mutant. In conclusion, this study further confirmed VirD5 as the plant transcription activator and identified as the first target gene of VirD5 in regulation.
我们之前曾报道过，毒力蛋白 VirD5 具有转录激活活性，能与特定的 DNA 元件 D5RE 结合，这对 VirD5 介导的稳定转化是必需的，但对瞬时转化则不是必需的。然而，VirD5 在植物转录调控中的作用还缺乏直接证据。在这项研究中，我们发现拟南芥基因 （编码 VirD5 反应 F-box 蛋白）受 VirD5 调控。 有两种 930 bp 和 1594 bp 的替代转录本，分别编码 309 个和 449 个氨基酸的 F-box 蛋白，分别命名为 D5RF.1 和 D5RF.2。与 D5RF.1 相比，D5RF.2 的 N 端延伸了 140 个氨基酸，两者都位于植物细胞核内。 的启动子包含两个 D5RE 元件，可被 VirD5 激活。当宿主植物被缺失 的 感染时，D5RF 的表达被下调。与 VirD5 类似，D5RF 也会影响 的稳定但不影响瞬时转化效率。在 突变体中，一些病原体响应基因的表达下调。综上所述，本研究进一步证实了 VirD5 是植物转录激活因子，并鉴定出 是 VirD5 在调控中的第一个靶基因。
