Abstract
The maintenance of genomic integrity requires coordination between DNA repair and replication. We investigated expression patterns of plant (rice) DNA repair genes such as CPD photolyase, UV-DDB1, CSB, PCNA, RPA32, FEN-1 and ORC1. We found that all the genes tested were expressed in proliferating tissues, but only CPD photolyase was expressed in non-proliferating tissue. The removal of DNA damages in both non-proliferating tissue and the proliferating tissues was observed under light conditions. In the dark, DNA damage in non-proliferating tissue was not repaired efficiently, but that in the proliferating tissues was removed rapidly. These results suggested that photoreactivation is the major DNA repair pathway in non-proliferating cells while dark repair is active in proliferating cells. Using a rice 22 K custom oligo DNA microarray, we found that most DNA repair genes were more strongly expressed in proliferationg tissues. These results indicate that plant dark repair is coordinated with DNA replication.
