The B-Box Domain Protein BBX21 Promotes Photomorphogenesis

BZS1, a B-box protein, promotes photomorphogenesis downstream of both brassinosteroid and light signaling pathways.

Photomorphogenesis is controlled by multiple signaling pathways, including the light and brassinosteroid (BR) pathways. BR signaling activates the BZR1 transcription factor, which is required for suppressing photomorphogenesis in the dark. We identified a suppressor of the BR hypersensitive mutant bzr1-1D and named it bzr1-1D suppressor1-Dominant (bzs1-D). The bzs1-D mutation was caused by over...

and Xing - Wang Deng Photomorphogenesis , B - Box Transcription Factors

BBX21, an Arabidopsis B-box protein, directly activates HY5 and is targeted by COP1 for 26S proteasome-mediated degradation.

BBX21 (also known as SALT TOLERANCE HOMOLOG 2), a B-box (BBX)-containing protein, has been previously identified as a positive regulator of light signaling; however, the precise role of BBX21 in regulating seedling photomorphogenesis remains largely unclear. In this study, we report that CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) interacts with BBX21 in vivo and is able to ubiquitinate BBX21 in v...

The Arabidopsis B-BOX protein BBX25 interacts with HY5, negatively regulating BBX22 expression to suppress seedling photomorphogenesis.

ELONGATED HYPOCOTYL5 (HY5) is a basic domain/leucine zipper (bZIP) transcription factor, central for the regulation of seedling photomorphogenesis. Here, we identified a B-BOX (BBX)-containing protein, BBX25/SALT TOLERANCE HOMOLOG, as an interacting partner of HY5, which has been previously found to physically interact with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1). BBX25 physically interacts with ...

Photomorphogenesis , B - Box Transcription Factors , and the Legacy of Magnus Holm

How plants perceive and respond to light has fascinated us for millennia and was first noted by Aristotle in De Anima. Erasmus Darwin must also have reflected on it in his garden, as evidenced by several lines in The Botanic Garden, his epic poem about plant life published in 1789. Almost 100 years later, the first rigorous research on phototropism was performed by his grandson Charles Darwin, ...