Abstract
In plant cells, mechanisms for regulation among organelles and nuclear DNA replication have not been elucidated. Using quantitative PCR analysis, we have already presented that organelle DNA replication (ODR) regulate nuclear DNA replication (NDR) and the tetrapyrrole intermediates protoporphyrin IX or Mg-protoporphyrin IX acts as a signaling molecule to regulate the initiation of NDR. It indicates that the novel function and the importance of organelle to regulate the progression of nuclear DNA replication via retrograde signal. Here we monitored ODR and NDR by directly counting intensity of the DAPI stained DNA contents by fluorescence microscopy. And we measured intracellular accumulation of ProtoIX and Mg-ProtoIX through the G1 and S phases. As a result, transient accumulation of Mg-ProtoIX, which is correlating with the ODR occurrence, was observed.
