The Arabidopsis Zinc Finger Protein 3 integrates ABA and light signaling in seed germination and plant development
ZFP3, a nuclear C2H2 zinc finger protein acts as a negative regulator of ABA- suppressed germination. Regulated over-expression of ZFP3 and closely related ZFP1, ZFP4, ZFP6 and ZFP7 confers ABA insensitivity to seed germination while the zfp3,zfp4 double mutant displays enhanced ABA susceptibility. Reduced expression of a large set of ABA-induced genes such as RAB18 and transcription factors ABI3, ABI4, ABI5 and RGL2 in ZFP3ox seedling suggests that ZFP3 indeed negatively regulates ABA signaling. Analysis of ZFP3ox plants revealed multiple phenotypic alterations such as semidwarf growth habit, defects in fertility and enhanced sensitivity of hypocotyl elongation to red but not to far-red or blue light. Analysis of genetic interactions with phytochrome and abi mutants suggested that ZFP3 amplifies red light signals perceived by photoreceptors other than phyB, and controlled by ABI5 downstream of ZFP3. Overall design: Comparison of ZFP3 overexpressing and wild type Arabidopsis seedlings