Abstract
Cyanidioschyzon merolae is a unicellular red alga found in acidic hot springs. The cell contains one nucleus, one mitochondrion, and one plastid, each with its own genome. C. merolae has been proposed as the primitive phototrophic eukaryote because of its extremely simple cell structure and minimally redundant small genome. C. merolae has therefore been developed as a model organism for investigating the basic architecture of photosynthetic eukaryotes.
The GFP reporter system is a powerful tool for investigating the subcellular localization of the target protein. Here, we show the establishment of GFP reporter system in C. merolae. In this system, we adopted the promoter of apcC gene, encoding phycocyanin-associated rod linker protein in the nucleus genome. ApcC has been predicted to locate in plastid, and the position of its signal sequence is deduced from comparative study. GFP protein expressed from the apcC promoter was clearly localized in cytosol, whereas GFP fused with the N-terminal or the ORF region of ApcC was localized in the plastid, consistent with the bioinformatic prediction. These results indicate that this reporter system is also effective in C. merolae.
