Abstract
Cyclobutane pyrimidine dimer (CPD) is a major type of UV-induced DNA damage. CPD photolyase is a crucial factor for determining the sensitivity of rice to UVB. We previously reported that the native rice CPD photolyase is phosphorylated. To investigate the effect of phosphorylation on CPD photolyase activity, we separated phosphorylated and unphosphorylated CPD photolyase from the native rice CPD photolyase, and then we measured the activity of each CPD photolyase. As a result, there was no difference in the activity between phosphorylated and unphosphorylated CPD photolyase. Furthermore, we found that CPD photolyase localizes to chloroplasts, mitochondria and nuclei and efficiently repairs UVB induced CPDs in all three organelles in rice plants. We prepared organelle-enriched fractions from rice plants, and detected CPD photolyase phosphorylated status. Mitochondria demonstrated a high proportion of non-phosphorylated CPD photolyase, whereas nuclei and chloroplasts had a relatively high proportion of the phosphorylated form.
