Abstract
Chloroplasts were originally established in eukaryotes by the endosymbiosis of a cyanobacterium, and chloroplast division apparatus were derived from the ancestral bacterial endosymbionts and the eukaryotic host. Because many of the cell division genes of the cyanobacteria are lost from the plant genome, it is expected that a lot of chloroplast division proteins derived from the eukaryotic host is an unknown. To identify and characterize novel chloroplast division proteins, we screened chloroplast division mutant from activation tagging lines and FOX (full-length cDNA overexpressor) lines in Arabidopsis. As a result of screening from about 30,000 lines, several novel chloroplast division mutants were found and it was thought that one of them was originated from the eukaryotic host. The cause gene encoded unknown function protein, which was predicted to have a chloroplast transit peptide and a coiled-coil motif, one membrane-spanning region. We would discuss the function of the novel chloroplast division protein.
