Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China.
Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China.
J Plant Physiol. 2021 Aug;263:153447. doi: 10.1016/j.jplph.2021.153447. Epub 2021 May 24.
SUMOylation, which transfers the Small Ubiquitin-related Modifier (SUMO) polypeptides to target proteins, regulates diverse cellular processes in eukaryotes. The SUMO conjugation reaction is usually promoted by SUMO E3 ligases, but the molecular functions of this type of enzymes remain unclear in cereal crops. Here, OsMMS21, a SUMO E3 ligase, was functionally characterized in rice (Oryza sativa). Bioinformatics analysis showed that OsMMS21 harbors a conserved SP-RING domain that is essential for the activity of SUMO ligases. Biochemical data indicated that this protein is auto-SUMOylated. Besides, overexpression of OsMMS21 rescued the developmental defects of the AtMMS21 mutant, supporting that OsMMS21 is a functional homolog of the Arabidopsis SUMO ligase AtMMS21. The OsMMS21 rice T-DNA mutant displays a short-root and dwarfism phenotype. RNA-seq data revealed that the expression levels of many genes involved in signaling transduction of hormones, including auxin, are altered in the OsMMS21 mutant. Further results under the auxin treatment showed that the OsMMS21 mutant is insensitive to auxin. Collectively, our results demonstrated the molecular features of OsMMS21 and uncovered the roles of this SUMO ligase in development and auxin response, providing hints for further studies on protein SUMOylation in rice.
SUMOylation 将 Small Ubiquitin-related Modifier（SUMO）多肽转移到靶蛋白上，调节真核生物中的多种细胞过程。SUMO 缀合反应通常由 SUMO E3 连接酶促进，但这种酶的分子功能在谷类作物中仍不清楚。在这里，水稻（Oryza sativa）中的 SUMO E3 连接酶 OsMMS21 被功能表征。生物信息学分析表明，OsMMS21 含有一个保守的 SP-RING 结构域，该结构域对于 SUMO 连接酶的活性是必需的。生化数据表明该蛋白是自身 SUMO 化的。此外，过表达 OsMMS21 挽救了 AtMMS21 突变体的发育缺陷，支持 OsMMS21 是拟南芥 SUMO 连接酶 AtMMS21 的功能同源物。OsMMS21 水稻 T-DNA 突变体表现出短根和矮化表型。RNA-seq 数据显示，许多参与激素信号转导的基因，包括生长素，在 OsMMS21 突变体中的表达水平发生了改变。在生长素处理下的进一步结果表明，OsMMS21 突变体对生长素不敏感。总之，我们的结果展示了 OsMMS21 的分子特征，并揭示了这种 SUMO 连接酶在发育和生长素响应中的作用，为进一步研究水稻中蛋白质 SUMO 化提供了线索。
