Abstract
Plastids have their own genome and gene expression apparatus derived from endosymbiosis of ancestral cyanobacteria. During subsequent evolution, plastids lost their autonomy and most of function became under nuclear control. In this study, we used the primitive, unicellular red alga Cyanidioschyzon melorae. This alga shows ancestral characteristics on many aspects including plastid genome or transcriptional regulation. Therefore, this organism can be helpful to understand evolution of regulation systems.
Here we used run-on system to understand transcriptional regulation in C. melorae chloroplasts. To examine light-dependent transcription, C. melorae cells were shifted in the dark for 12h, followed by re-illumination for 1h or 6h. Intact chloroplasts were isolated from cells to perform run-on transcription assays. Transcriptional activity was transiently induced after 1 hour light, but declined to the half after 6 hours. This result correlates with microarray analysis, suggesting that gene expression in C. melorae chloroplasts are mainly regulated at transcriptional level.
