Activation of C2H2-type Zinc Finger Genes Induces Dwarfism in Arabidopsis thaliana

Zinc finger proteins compose one of the largest transcription factor families in plants, but only a handful have been functionally specified in plant growth. In this study, a semidominant mutant, Arabidopsis thaliana dwarf1 (Atdwa1), was discovered from activation tagging screening using the SKI015 T-DNA vector. The Atdwa1 mutant displayed severe dwarfism and loss of apical dominance, as well as other pleiotropic defects, such as earlier flowering, fewer leaves, and shorter sliliques than those of the wild-type plant Thermal asymmetric interlaced- polymerase chain reaction analysis revealed that activated T-DNA was inserted into the At5g54330 gene, disrupting its coding sequence. We also demonstrated that At5g54330 expression was nullified by the insertion, whereas expression of its downstream genes, At5g54340, At5g54350, and At5g54360, were activated. A database search revealed that all three downstream genes encode proteins related to C2H2-type zinc finger proteins. Overexpression of each gene resulted in dwarfism similar to that of Atdwa1. These findings indicate that Atdwa1 mutant was caused by synergistic manifestation of concomitant activation of At5g54340 to At5g54360, and that the zinc finger proteins may play a role in regulation of plant growth and development.