Abstract
Plastid is a typical organelle in plants, showing a spectrum of differentiation according to plant development. It is known that the plastid contains its own genome in the form of nucleoids, comprising a circular DNA of 120-150 kbp depending on plant species, and various proteins including DNA polymerase and RNA polymerases. We propose a new approach for isolation of plastid nucleoids. The PEND protein is a DNA-binding protein and a DNA-binding domain called cbZIP is present at its N-terminus. In transformants of Arabidopsis thaliana cbZIP-GFP fusion proteins were localized in the nucleoids of plastids. Plastid nucleoids were isolated from various tissues using GFP antibody, and determined proteins of plastid nucleoids by peptide mass fingerprint.
