Phosphorylation of RNA Polymerase II by CDKC;2 Maintains the Arabidopsis Circadian Clock Period

• Published in: Plant and cell physiology 2022-04, Vol.63 (4), p.450-462
• Main Authors: Uehara, Takahiro N, Nonoyama, Takashi, Taki, Kyomi, Kuwata, Keiko, Sato, Ayato, Fujimoto, Kazuhiro J, Hirota, Tsuyoshi, Matsuo, Hiromi, Maeda, Akari E, Ono, Azusa, Takahara, Tomoaki T, Tsutsui, Hiroki, Suzuki, Takamasa, Yanai, Takeshi, Kay, Steve A, Itami, Kenichiro, Kinoshita, Toshinori, Yamaguchi, Junichiro, Nakamichi, Norihito
• Format: Article
• Language: English
• Subjects: Animals; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Circadian Clocks - genetics; Circadian Rhythm - genetics; Editor's Choice; Gene Expression Regulation, Plant; Mammals - metabolism; Phosphorylation; Rapid Paper; RNA Polymerase II - genetics; RNA Polymerase II - metabolism
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcac011

Abstract The circadian clock is an internal timekeeping system that governs about 24 h biological rhythms of a broad range of developmental and metabolic activities. The clocks in eukaryotes are thought to rely on lineage-specific transcriptional–translational feedback loops. However, the mechanisms underlying the basic transcriptional regulation events for clock function have not yet been fully explored. Here, through a combination of chemical biology and genetic approaches, we demonstrate that phosphorylation of RNA polymerase II by CYCLIN DEPENDENT KINASE C; 2 (CDKC;2) is required for maintaining the circadian period in Arabidopsis. Chemical screening identified BML-259, the inhibitor of mammalian CDK2/CDK5, as a compound lengthening the circadian period of Arabidopsis. Short-term BML-259 treatment resulted in decreased expression of most clock-associated genes. Development of a chemical probe followed by affinity proteomics revealed that BML-259 binds to CDKC;2. Loss-of-function mutations of cdkc;2 caused a long period phenotype. In vitro experiments demonstrated that the CDKC;2 immunocomplex phosphorylates the C-terminal domain of RNA polymerase II, and BML-259 inhibits this phosphorylation. Collectively, this study suggests that transcriptional activity maintained by CDKC;2 is required for proper period length, which is an essential feature of the circadian clock in Arabidopsis.