ARABIDOPSIS HY8 LOCUS ENCODES PHYTOCHROME-A

Citation
K. Dehesh et al., ARABIDOPSIS HY8 LOCUS ENCODES PHYTOCHROME-A, The Plant cell, 5(9), 1993, pp. 1081-1088
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology,"Plant Sciences
Journal title
ISSN journal
1040-4651
Volume
5
Issue
9
Year of publication
1993
Pages
1081 - 1088
Database
ISI
SICI code
1040-4651(1993)5:9<1081:AHLEP>2.0.ZU;2-C
Abstract
hy8 long hypocotyl mutants of Arabidopsis defective in responsiveness to prolonged far-red light (the so-called ''far-red high-irradiance re sponse'') are selectively deficient in functional phytochrome A. To de fine the molecular lesion in these mutants, we sequenced the phytochro me A gene (phyA) in lines carrying one or other of two classes of hy8 alleles. The hy8-1 and hy8-2 mutants that express no detectable phytoc hrome A each have a single nucleotide change that inserts a translatio nal stop codon in the protein coding sequence. These results establish that phyA resides at the HY8 locus. The hy8-3 mutant that expresses w ild-type levels of photochemically active phytochrome A has a glycine- to-glutamate missense mutation at residue 727 in the C-terminal domain of the phyA sequence. Quantitative fluence rate response analysis sho wed that the mutant phytochrome A molecule produced by hy8-3 exhibited no detectable regulatory activity above that of the phyA-protein-defi cient hy8-2 mutant. This result indicates that glycine-727, which is i nvariant in all sequenced phytochromes, has a function important to th e regulatory activity of phytochrome A but not to photoperception.