title: Impaired splicing of phytochrome B pre-mRNA in a novel phyB mutant of Arabidopsis.
abstract: Phytochrome is the red/far-red absorbing photoreceptor active in photomorphogenesis, the apoprotein of which is encoded by a small gene family (PHYA, PHYB, PHYC, PHYD and PHYE). A novel phytochrome B-deficient mutant, phyB-103, was isolated from a screen of EMS-mutagenised Arabidopsis M2 seed. phyB-103 carries a G-to-A base substitution at the 5' splice site +1 G nucleotide of intron 1 of PHYB. The phyB-103 PHYB transcript is larger than the wild-type PHYB transcript and DNA sequence analysis showed that the entire intron is retained in the mature PHYB transcript of phyB-103. Thus the phyB-103 G-to-A substitution prevents intron splicing. The retained intron contains within it an in-frame stop codon, and the predicted PHYB-003 apoprotein thus terminates prematurely. phyB-103 is therefore likely to be a null allele of PHYB, consistent with the observation that the phenotype conferred by phyB-103 is as severe as that conferred by previously described phyB null alleles.
authors.affiliation: John Innes Centre, Colney, Norwich, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Bradley
authors.forename: G C
authors.initials: GC
authors.lastname: Whitelam
authors.forename: N P
authors.initials: NP
authors.lastname: Harberd
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D017931:DNA Primers; D007438:Introns; D008969:Molecular Sequence Data; D009154:Mutation; D010786:Photoreceptor Cells; D010834:Phytochrome / Q000235:genetics*; D051939:Phytochrome B; D016133:Polymerase Chain Reaction; D012322:RNA Precursors / Q000235:genetics*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D014157:Transcription Factors
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers; C497952:PHYB protein, Arabidopsis; D012322:RNA Precursors; D012333:RNA, Messenger; D014157:Transcription Factors; D010834:Phytochrome; D051939:Phytochrome B; D012194:RNA-Directed DNA Polymerase