An mRNA cap binding protein, ABH1, modulates early abscisic acid signal transduction in Arabidopsis.
The plant hormone abscisic acid (ABA) regulates important stress and developmental responses. We have isolated a recessive ABA hypersensitive mutant, abh1, that shows hormone specificity to ABA. ABH1 encodes the Arabidopsis homolog of a nuclear mRNA cap binding protein and functions in a heterodimeric complex to bind the mRNA cap structure. DNA chip analyses show that only a few transcripts are down-regulated in abh1, several of which are implicated in ABA signaling. Consistent with these results, abh1 plants show ABA-hypersensitive stomatal closing and reduced wilting during drought. Interestingly, ABA-hypersensitive cytosolic calcium increases in abh1 guard cells demonstrate amplification of early ABA signaling. Thus, ABH1 represents a modulator of ABA signaling proposed to function by transcript alteration of early ABA signaling elements.
Hugouvieux
V
V
Division of Biology, Cell and Developmental Biology Section, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
Kwak
J M
JM
Schroeder
J I
JI
D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000502:physiology*; D029681:Arabidopsis Proteins; D015152:Blotting, Northern; D002118:Calcium / Q000378:metabolism; D004843:Epistasis, Genetic; D017930:Genes, Reporter; D006801:Humans; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D010937:Plant Growth Regulators / Q000494:pharmacology; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D020798:Two-Hybrid System Techniques
D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D002118:Calcium; D010937:Plant Growth Regulators; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C435105:At2g13540 protein, Arabidopsis