Complementation assay to evaluate the role of putative aminotransferase in Arabidopsis

after completion of the Arabidopsis genome sequencing project and identification of 25498 genes, the function of several genes defined putatively. For instance the function of seven genes in Arabidopsis defined as putative tyrosine aminotransferas which the function of three genes have been confirmed experimentally until now. In the present study, the function of putative gene from this family considered to be evaluated using complementation test with DL39 auxotroph bacteria. As a result of mutation in tyrosine aminotransferase gene, this bacterium is auxotroph for L-tyrosine amino acid. In order to evaluate the ability of Arabidopsis putative tyrosine aminotransferase gene to complement tyrosine aminotransferase deficiency in bacteria, the coding region of this gene was cloned into pQE expression vector and used for bacterial transformation. Successful complementation results in the restoration of the bacterial ability to grow in medium without L-tyrosine supplementation. Analysis of enzyme assay showed that the enzyme is able to catalyzes the conversion of tyrosine to 4-hydroxyphenylpyruvate. These results confirmed that this putative gene has tyrosine aminotransferase activity.