講師資料
Talks：
A repressive network on the evening complex assists the circadian clock stability in Arabidopsis
阿拉伯芥藉由轉錄網絡抑制夜間蛋白複合體來穩定生理時鐘運行節律
Name：
蔡皇龍（Huang-Lung Tsai）
Position：
Associate Professor
Affiliation：
Institute of Molecular and Cellular Biology, National Taiwan University
Email：
Photo：
Research Interests：
Most organisms on Earth have evolved circadian clocks to regulate the oscillations of multiple physiological pathways in sync with the approximately 24-h period, driven by the day-night cycles resulting from Earth’s rotation. These oscillations are known as “circadian rhythms”. In addition to the predictable day-night and seasonal cycles, plants, being sessile, are exposed to numerous unpredictable and transient changes during their growth and development. The rhythmicity of the circadian clock helps plants stay on track without overreacting to random cues, thereby ensuring optimal growth and reproduction during the appropriate seasons.
The circadian clock consists of genes tightly interlocked in regulatory feedback loops, where clock-related genes are directly or indirectly regulated by their downstream genes. these feedback loops cause genes to peak at specific times of the day and oscillate in response to external cues like light and temperature throughout the day-night cycles.
In the model plant, Arabidopsis, BASIC PENTACYSTEINE (BPC) family members, which are plant-specific transcription factors that bind to developmentally crucial cis-elements called GAGA motifs, play a significant role in clock regulation. The BPC genes form a complex transcriptional network that includes both activating and repressive functions on their downstream targets, including other members within the BPC family. We are particularly interested in elucidating mechanisms underlying the interaction between the BPC gene network and the circadian clock, to better understand how these two systems influence each other.
Selected Publications：
1. Yi-Chen Lee, Pei-Ting Tsai, Xun-Xian Huang and Huang-Lung Tsai* (2022, May). Family members additively repress the ectopic expression of BASIC PENTACYSTEINE3 to prevent disorders in Arabidopsis circadian vegetative development. Frontiers in Plant Science, 13: 919946. (*corresponding author)
2. Neda Sanobar, Pin-Chun Lin, Zhao-Jun Pan, Ru-Ying Fang, Veny Tjita, Fang-Fang Chen, Hao-Ching Wang, Huang-Lung Tsai, Shu-Hsing Wu, Tang-Long Shen, Yan-Huey Chen and Shih-Shun Lin (2021, Sep). Investigating the Viral Suppressor HC-Pro Inhibiting Small RNA Methylation through Functional Comparison of HEN1 in Angiosperm and Bryophyte. Viruses, 13(9): 1837.
Abstract：
The members of the BASIC PENTACYSTEINE (BPC) family are plant-specific transcription factors that bind to GAGA motifs. In Arabidopsis, the network formed by the overlapping and antagonistic functions of class I (BPC1, BPC2, BPC3) and class II (BPC4, BPC6) members has a repressive effect on multiple essential genes of the circadian clock. The simultaneous absence of BPC1 and BPC2 is detrimental to circadian clock rhythmicity. However, further removal of BPC3 partially recovers the clock defect. Genetic studies on bpc4,6 double mutant revealed the fact that class I BPCs alone can sustain a clock similar to that in wild-type plants. To clarify how BPCs affect the circadian clock, we introduced overexpression of BPC3 in transgenic Arabidopsis. This overexpression triggered a chain reaction among clock genes: the morning-phased CCA1 and evening-phased ELF4 were drastically repressed and the transcript levels of PSEUDORESPONSE REGULATORs (PRRs) were altered in a gradient from high to low. The oscillation of evening genes including GI and TOC1, was damped at high transcript levels. Collectively, the BPC network differentially represses clock genes. The vagueness of the net regulatory effect could be due to cryptic indirect pathways between the clock genes. Through a simulation test in the current model of the circadian clock, we illustrated that evening complex might serve as a cryptic entry point for the imbalanced BPC network, hindering the interlocking key regulators of the clock genes in Arabidopsis.
2024年會：
10/13 11:30 A repressive network on the evening complex assists the circadian clock stability in Arabidopsis
阿拉伯芥藉由轉錄網絡抑制夜間蛋白複合體來穩定生理時鐘運行節律 [會議室4]