Abstract
We previously found that higher cyclobutane pyrimidine dimer (CPD) photorepair activity was observed in nucleus-rich fraction, but not in chloroplast-rich fraction. In these experiments, each nucleus- and chloroplast-rich fraction obtained from leaves by sucrose density gradient centrifugation was used. This study was aimed to reconfirm the above results and to study whether CPD photorepair ability is involved in mitochondria. We measured UVB-induced CPDs and their photorepair and darkrepair in each organellar genome in intact leaves by Real-time PCR. rbcS, cab and phr (nuclear genome-encoded genes), cox3, cob and orf288 (mitochondria genome-encoded genes) and atpB and rbcL (chloroplast genome-encoded genes) were targeted for analysis. DNA lesions were found to be induced in all of these genes by UV-B. On the other hand, photorepair was observed in nucleus and mitochondria, but not in chloroplast. Little or no excision repair was observed in all of organellars.