Characterization of a protein phosphatase type 2C (APC4) in Arabidopsis thaliana by using T-DNA insertion mutants

Abstract

Protein phosphorylation and dephosphorylation play important roles in signal transduction pathways. We have focused on a PP2C in Arabidopsis thaliana that has a similarity with PP2C in yeast (PTC), and named APC4. It has been reported that PTC negatively regulated stress-responsive signaling pathway. So far, we have confirmed that APC4 has enzymatic properties of PP2C. In order to clarify its function in vivo, we have screened T-DNA tag lines in A. thaliana and isolated two independent lines. In one of these T-DNA insertion lines, we have not obtained any homozygous plants, and the abnormal segregation ratio between wild type and heterozygous mutant plants was observed. Defective APC4 mRNA by T-DNA insertion has been detected in heterozygous plants by northern analysis, suggesting that a mutant protein may act dominant-negatively. Now, we try to analyze the function of APC4 by using over-expressing plants.