Expression pattern of Aux/IAA genes in the iaa3/shy2-1D mutant of Arabidopsis thaliana (L.).
A semi-dominant mutant suppressor of hy2 (shy2-1D) of Arabidopsis thaliana, originally isolated as a photomorphogenesis mutant, shows altered auxin responses. Recent molecular cloning revealed that the SHY2 gene is identical to the IAA3 gene, a member of the primary auxin-response genes designated the Aux/IAA gene family. Because Aux/IAA proteins are reported to interact with auxin response factors, we investigated the pattern of expression of early auxin genes in the iaa3/shy2-1D mutant. RNA hybridization analysis showed that levels of mRNA accumulation of the early genes were reduced dramatically in the iaa3/shy2-1D mutants, although auxin still enhanced gene expression in the iaa3/shy2-1D mutant. Histochemical analysis using a fusion gene of the auxin responsive domain (AuxRD) and the GUS gene showed no IAA-inducible GUS expression in the root elongation zone of the iaa3/shy2-1D mutant. On the other hand, ectopic GUS expression occurred in the hypocotyl, cotyledon, petiole and root vascular tissues in the absence of auxin. These results suggest that IAA3/SHY2 functions both negatively and positively on early auxin gene expression.
Oono
Yutaka
Y
Advanced Science Research Center, Japan Atomic Energy Research Institute, Takasaki, Gunma. yoono@taka.jaeri.go.jp
Ooura
Chiharu
C
Uchimiya
Hirofumi
H
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins; D003001:Cloning, Molecular; D018548:Cotyledon / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005816:Genetic Complementation Test; D006579:Heterozygote; D006720:Homozygote; D018546:Hypocotyl / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000302:isolation & purification
D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; C117994:SHY2 protein, Arabidopsis; C030737:indoleacetic acid