PT  - JOURNAL ARTICLE
AU  - Fry, Rebecca C.
AU  - Habashi, Jessica
AU  - Okamoto, Haruko
AU  - Deng, Xing Wang
TI  - Characterization of a Strong Dominant <em>phytochrome A</em>Mutation Unique to Phytochrome A Signal Propagation
AID  - 10.1104/pp.005264
DP  - 2002 Sep 01
TA  - Plant Physiology
PG  - 457--465
VI  - 130
IP  - 1
4099  - http://www.plantphysiol.org/content/130/1/457.short
4100  - http://www.plantphysiol.org/content/130/1/457.full
SO  - Plant Physiol.2002 Sep 01; 130
AB  - Here, we report the isolation and characterization of a strong dominant-negative phytochrome A(phyA) mutation (phyA-300D) in Arabidopsis. This mutation carries a single amino acid substitution at residue 631, from valine to methionine (V631M), in the core region within the C-terminal half of PHYA. This PHYA core region contains two protein-interactive motifs, PAS1 and PAS2. Val-631 is located within the PAS1 motif. The phyA-V631M mutant protein is photochemically active and accumulates to a level similar to wild type in dark-grown seedlings. Overexpression of PHYA-V631M in a wild-type background results in a dominant-negative interference with endogenous wild-type phyA, whereas PHYA-V631M in aphyA null mutant background is inactive. To investigate the specificity of this mutation within the phytochrome family, the corresponding amino acid substitution (V664M) was created in the PHYTOCHROME B (PHYB) polypeptide. We found that the phyB-V664M mutant protein is physiologically active in phyB mutant and causes no interfering effect in a wild-type background. Together, our results reveal a unique feature in phyA signal propagation through the C-terminal core region.