Arabidopsis HEMERA/pTAC12 Initiates Photomorphogenesis by Phytochromes

作者：Chen Meng^*; Galvao Rafaelo M; Li Meina; Burger Brian; Bugea Jane; Bolado Jack; Chory Joanne

来源：Cell, 2010, 141(7): 1230-U237.

DOI：10.1016/j.cell.2010.05.007

Light plays a profound role in plant development, yet how photoreceptor excitation directs phenotypic plasticity remains elusive. One of the earliest effects of light is the regulated translocation of the red/far-red photoreceptors, phytochromes, from the cytoplasm to subnuclear foci called phytochrome nuclear bodies. The function of these nuclear bodies is unknown. We report the identification of hemera, a seedling lethal mutant of Arabidopsis with altered phytochrome nuclear body patterns. hemera mutants are impaired in all phytochrome responses examined, including proteolysis of phytochrome A and phytochrome-interacting transcription factors. HEMERA was identified previously as pTAC12, a component of a plastid complex associated with transcription. Here, we show that HEMERA has a function in the nucleus, where it acts specifically in phytochrome signaling, is predicted to be structurally similar to the multiubiquitin-binding protein, RAD23, and can partially rescue yeast rad23mutants. Together, these results implicate phytochrome nuclear bodies as sites of proteolysis.

• 出版日期2010-6-25