VISUALIZATION OF THE CHROMOSOME SCAFFOLD IN A PRIMITIVE EUKARYOTE DINOFLAGELLATE Crypthecoainium cohnii

The chromosome scaffolds in higher eukaryotic nuclei have been described elsewhere. Butit is unknown when they evolved. The dinoflagellates are the primitive organisms that maybe the intermediate between prokaryotes and eukaryotes. Combining chromosome scaffold prep-aration methods with embedment-free section microscopy,we demonstrate that the dino-flagellate Crypthecodinium cohnii chromosome retains a protein scaffold after the depletionof DNA and soluble proteins. This scaffold preserves the morphology characteristic of thechromosome. Two-dimensional electrophoreses show that the chromosome scaffolds are mainlycomposed of acidic proteins. Our results suggest that a framework similar to the chromosomescaffold in the mammalian cell appeared in the primitive eukaryote. We propose that thechromosome scaffold possibly originated from the early stages of eukaryote evolution.

VISUALIZATION OF THE CHROMOSOME SCAFFOLD IN A PRIMITIVE EUKARYOTE DINOFLAGELLATE Crypthecoainium cohnii

The chromosome scaffolds in higher eukaryotic nuclei have been described elsewhere. But it is unknown when they evolved. The dinoflagellates are the primitive organisms that may be the intermediate between prokaryotes and eukaryotes. Combining chromosome scaffold prep- aration methods with embedment-free section microscopy,we demonstrate that the dino- flagellate Crypthecodinium cohnii chromosome retains a protein scaffold after the depletion of DNA and soluble proteins. This scaffold preserves the morphology characteristic of the chromosome. Two-dimensional electrophoreses show that the chromosome scaffolds are mainly composed of acidic proteins. Our results suggest that a framework similar to the chromosome scaffold in the mammalian cell appeared in the primitive eukaryote. We propose that the chromosome scaffold possibly originated from the early stages of eukaryote evolution.