Abstract
Cyclobutane pyrimidine dimer (CPD) photolyase is a critical factor for determining UVB sensitivity in plant. We previously reported that the native rice CPD photolyase was phosphorylated. However, it is unclear that the function of phosphorylated CPD photolyase in rice in vivo. To understand the in vivo function of CPD photolyase, we tried to identify the protein kinase that phosphorylates rice CPD photolyase.
First, we investigated phosphorylation state of rice CPD photolyase during in development of leaf, in etiolated seedling, or in cultured cell. Both phosphorylated and unphosphorylated CPD photolyases were present at any sample that we examined. Furthermore, we found that unphosphorylated CPD photolyase was phosphorylated by mixture of insect cell extract. These results mean that protein kinase, which can phosphorylate the rice CPD photolyase, was contained in insect cell extract. Next, we analyzed biochemical properties of protein kinase which was contained in insect cell extract. As a result, Mg2+ was required for phosphorylation of rice CPD photolyase.
