INVESTIGADORES
YANOVSKY Marcelo Javier
artículos
Título:
Missense mutation in the PAS2 domain of phytochrome A impairs subnuclear localization and a subset of responses.
Autor/es:
YANOVSKY, MJ; LUPPI, J; KIRCHBAUER, D; OGORODNIKIVA, O; SINESCHEKOV, V; ADAM, E; KIRCHER, S; STANELONI, R; SCHAFER, E; NAGY, F; CASAL, JJ
Revista:
PLANT CELL
Referencias:
Año: 2002 vol. 14 p. 1591 - 1603
ISSN:
1040-4651
Resumen:
Phytochrome A signaling shows two photobiologically discrete outputs: so-called very-low-fluence responses (VLFR) and high-irradiance responses (HIR). By modifying previous screening protocols, we isolated two Arabidopsis mutants retaining VLFR and lacking HIR. Phytochrome A negatively or positively regulates phytochrome B signaling, depending on light conditions. These mutants retained the negative but lacked the positive regulation. Both mutants carry the novel phyA-302 allele, in which Glu-777 (a residue conserved in angiosperm phytochromes) changed to Lys in the PAS2 motif of the C-terminal domain. The phyA-302 mutants showed a 50% reduction in phytochrome A levels in darkness, but this difference was compensated for by greater stability under continuous far-red light. phyA-302:green fluorescent protein fusion proteins showed normal translocation from the cytosol to the nucleus under continuous far-red light but failed to produce nuclear spots, suggesting that nuclear speckles could be involved in HIR signaling and phytochrome A degradation. We propose that the PAS2 domain of phytochrome A is necessary to initiate signaling in HIR but not in VLFR, likely via interaction with a specific partner.