You are not currently logged in.
Access your personal account or get JSTOR access through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Biochemical Characterization of Arabidopsis Wild-Type and Mutant Phytochrome B Holoproteins
Tedd D. Elich and Joanne Chory
The Plant Cell
Vol. 9, No. 12 (Dec., 1997), pp. 2271-2280
Published by: American Society of Plant Biologists (ASPB)
Stable URL: http://www.jstor.org/stable/3870584
Page Count: 10
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Although phytochrome B (phyB) plays a particularly important role throughout the life cycle of a plant, it has not been studied in detail at the molecular level due to its low abundance. Here, we report on the expression, assembly with chromophore, and purification of epitope-tagged Arabidopsis phyB. In addition, we have reconstructed two missense mutations, phyB-4 and phyB-101, isolated in long hypocotyl screens. We show that mutant proteins phyB-4 and phyB-101 exhibit altered spectrophotometric and biochemical properties relative to the wild-type protein. In particular, we demonstrate that phyB-101 Pfr exhibits rapid nonphotochemical (dark) reversion to Pr that results in a lower photoequilibrium level of the active Pfr form. We conclude that this occurs in vivo as well because phyB-101 mutants are shown to lack an end-of-day-far-red hypocotyl elongation response that requires a stable Pfr species. We propose that this Pfr instability may be the primary molecular mechanism underlying the phyB-101 mutant phenotype.
The Plant Cell © 1997 American Society of Plant Biologists (ASPB)