Abstract
The unicellular red alga Cyanidioschyzon merolae contains a single cell nucleus, a plastid and a mitochondrion, and is thought to be useful in investigation of evolution of plastid in the lineage other than green plants. We isolated plastid nucleoids from C. merolae, and analyzed the basic properties of in vitro transcription. Rifampicin that inhibit transcription of bacterial RNA polymerase have different effects on the nucleoids of C. merolae, green plants and cyanobacteria.
A homologue of bacterial histone-like protein HU is present in the plastid nucleoids of C. merolae, and this protein has ability to compact DNA, while sulfite reductase compacts DNA in the nucleoids of pea plastids. The in vitro transcription activity of plastid nucleoids of C. merolae was activated by the addition of recombinant HU, but the transcription in pea nucleoids was decreased. Nucleoid proteins have different effects in different lineages.
