Elucidating the specific steric structure of the plant hormone master transcription factor BIL1/BZR1

October 2, 2018

Brassinosteroids are plant hormones that mainly serve to promote plant growth and shape. The specific and diverse responses of gene expression caused by a master transcription factors in brassinosteroid signaling are essential for physiological regulation of plant.

The University of Tokyo and the RIKEN CSRS have determined the complex structure of the brassinosteroid master transcription factor BIL1/BZR1 and its target DNA by X-ray crystallography. This marks the first time a three-dimensional structure in the BZR family of transcription factors (which are high conserved in plants) has been elucidated. Researchers were able to explain the mechanism of base sequence recognition specific to BIL1/BZR1 at the molecular level by carrying out a detailed comparison with the steric structure of the bHLH family of transcription factors, which are similar to BIL1/BZR1 in their amino acid sequences and DNA binding characteristics.

The structural basis for brassinosteroid response by BIL1/BZR1 clarified in this research is evolutionarily conserved in a large number of higher plants, and it is presumed to be one of the mechanisms for generating the diversity of brassinosteroid response genes.

Original article
Nature Plants doi:10.1038/s41477-018-0255-1
S. Nosaki, T. Miyakawa, Y. Xu, A. Nakamura, K. Hirabayashi, T. Asami, T. Nakano, M. Tanokura,
"Structural basis for brassinosteroid response by BIL1/BZR1".
Takeshi Nakano
Senior Research Scientist
Gene Discovery Research Group