Protistology 12 (4), 163–172 (2018) |
Ultrastructural organization of the chromatin elements in chromosomes of the dinoflagellate Prorocentrum minimum |
1 A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| Submitted October 9, 2018 | Accepted October 26, 2018 | Summary DNA of the majority of present-day eukaryotes is folded with the aid of highly conserved histone proteins to form nucleosome fibers, which further condense via interactions with histones and non-histone chromatin proteins. Dinoflagellate chromatin is unique among eukaryotes, as their chromosomes lack the histones and remain condensed throughout the cell cycle. Here, we report the results of electron microscopy study of chromatin elements inside the chromosomes of potentially toxic planktonic dinoflagellate Prorocentrum minimum. We found that chromatin fibers inside the condensed chromosomes of P. minimum form not only arch-like structures, that were repeatedly described for various dinoflagellate species, but also rosette-like complexes with chromatin fibers radiating from its electron-dense center. The effects of histone loss in the evolution of dinoflagellates are discussed within the frames of the hierarchical chromatin folding paradigm.
Key words: protists, dinoflagellates, chromatin, chromosomes, chromatin folding, nucleus, electron microscopy
Address for correspondence: Mariia Berdieva. Institute of Cytology of the Russian Academy of Sciences, Laboratory of Cytology of Unicellular Organisms, Tikhoretsky Ave. 4, 194064 St. Petersburg, Russia; e-mail: maria.berd4@yandex.ru |
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