講師資料
Talks：
BASIC PENTACYSTEINEs modulate the circadian clock by repressing the Evening Complex in Arabidopsis
阿拉伯芥BASIC PENTACYSTEINEs藉由抑制Evening Complex 調節生理時鐘運行節律
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：
BASIC PENTACYSTEINEs (BPCs) are plant-specific transcription factors that play a role in circadian clock regulation. The altered expression levels of target genes in various bpc mutant loci combinations suggest that BPC family members can act as repressors, activators, or both, to regulate the transcription of downstream clock genes in Arabidopsis. However, the immediate reactions of these genes to BPC ectopic expression don’t fully reveal the actual regulatory mechanism. This is most likely because the clock’s complex feedback loops are masking the true BPC effects. To investigate this, we enhanced the biological effects of BPC3, a family member with typically low expression, by overexpressing it. Using ChIP-seq, we mapped its genomic binding sites and found that BPC3 targets a range of clock genes with varying binding affinities, offering insight into how BPC proteins modulate the circadian clock. We then simulated the BPC3 binding effects within a publicly available mathematical model. The model’s results revealed an action path for BPC3 that aligns with the clock gene expression data observed after BPC3 overexpression. Our simulation specifically demonstrates that BPC3’s direct repression of ELF4 within the Evening Complex is the key event leading to the observed clock disruption. This finding positions the evening loop as the central regulatory hub for BPC-mediated clock modulation. 
2025年會：