On August 10th 2018, a research led by Professor Xing Wang Deng from SUSTech and Dr. Dongqing Xu from UT-Austin was published in The Plant Cell, entitled “B-box protein 28 negatively regulates photomorphogenesis by repressing HY5 activity and itself undergoes COP1-mediated degradation”. Visiting Scholar Dr. Fang Lin and Research Assistant Professor Dr. Yan Jiang from the Institute of Plant and Food Science, Department of Biology, are the co-first authors; Professor Jiansheng Liang and Miss Tingting Yan from SUSTech, Professor Liumin Fan and Dr. Jian Li from Peking University, Professor Z. Jeffrey Chen from UT-Austin are co-authors.

Sunlight is not only the major energy source for plants, but also acts as one of the most essential environmental factors affecting various physiological and developmental processes in plants. Plants have evolved a delicate molecular system to fine-tune their growth and development in response to dynamically changing light environments. In this study, we report that BBX28, an Arabidopsis B-box containing protein, negatively mediates the photomorphogenic development in a dose dependent manner in plants. BBX28 interferes with HY5’s binding to promoters of its target genes through physical interaction, thereby repressing HY5 activity and negatively affecting the HY5-regulated genes expression. In darkness, BBX28 associates with COP1 and undergoes COP1-mediated degradation via the 26S proteasome system. These results demonstrate that BBX28 acts as a key factor of COP1-HY5 regulatory hub in maintaining proper HY5 biochemical activity to ensure normal photomorphogenic development in plants. 

The study was supported by the Start-up Funding from SUSTech, National Natural Science Foundation of China, and Peking University-Tsinghua Life Science Joint Center.

Link to the paper： http://www.plantcell.org/content/early/2018/08/10/tpc.18.00226