Jiawei Xiong: The Plant Cell First Author

Jiawei Xiong, co-first author of “Inhibition of SIZ1-mediated SUMOylation of HOOKLESS1 promotes light-induced apical hook opening in Arabidopsis“

Current Position: Ph.D. candidate, Sichuan University

Education: Bachelor’s degree, Sichuan Agricultural University

Non-scientific Interests: Reading and watching movies

Brief bio: After my graduation from Sichuan Agricultural University in 2017, I began my doctoral study in Prof. Dawei Zhang’s research group, focused on the molecular mechanism of photomorphogenesis in plants. In this study, we demonstrate that the SUMO E3 ligase SIZ1 interacts with HLS1 and mediates HLS1 SUMOylation. Mutating SUMO attachment sites of HLS1 results in impaired function of HLS1, indicating that HLS1 SUMOylation is essential for its function. SUMOylated HLS1 is more likely to assemble into oligomers, which are the active form of HLS1. During the dark-to-light transition, light induces the quick opening of the apical hook, concomitantly with a drop in SIZ1 transcript levels, resulting in lower HLS1 SUMOylation. Furthermore, we discover that HY5 directly binds to the SIZ1 promoter and suppresses its transcription. HY5-initiated rapid apical hook opening partially depends on the HY5-SIZ1 transcriptional inhibition. Our study identifies a function for SIZ1 in apical hook development, providing a dynamic regulatory mechanism linking the post-translational modification of HLS1 during apical hook formation and light-induced apical hook opening.

姓名：熊佳威

目前职位：四川大学生命科学学院，在读博士生

教育背景：四川农业大学，学士学位

兴趣爱好：阅读，看电影

个人简介：在2017年从四川农业大学本科毕业后，我在张大伟教授的课题组开始攻读博士学位，主要研究植物光形态建成的分子机制。在本研究中，我们证明了SUMO E3连接酶SIZ1与HLS1相互作用并介导HLS1的SUMO化。突变HLS1的SUMO附着位点会导致HLS1的功能受损，这表明HLS1的SUMO化对其功能至关重要。SUMO化的HLS1更容易组装成活性的寡聚物形式。在从黑暗到光照的转换过程中，光诱导顶端钩的快速打开，同时伴随着SIZ1转录水平的下降，导致HLS1的SUMO化水平降低。此外，我们还发现HY5直接结合到SIZ1的启动子并抑制其转录。HY5介导的顶端钩快速打开是部分依赖于HY5-SIZ1的转录抑制。我们的研究揭示了SIZ1介导的HLS1的SUMO化在顶端钩发育过程中的重要作用，提出了一个将HLS1在顶端钩形成过程中的翻译后修饰与光诱导的顶端钩打开联系起来的动态调节机制。