Cell division, essential to life, varies astonishingly among organisms. A recent study by Dey's group at EMBL Heidelberg, published in
Nature, delves into the evolution of cell division methods in organisms closely related to animals and fungi. This research highlights the connection between the life cycles of organisms and their cell division techniques.
Illustration Image Pixabay
Animals and fungi, although separated by over a billion years, share numerous similarities as eukaryotes but diverge in several physiological processes, notably mitosis. The "open" mitosis of animal cells, where the nuclear envelope disintegrates, contrasts with the "closed" mitosis of fungi, where this envelope remains intact.
The origin of these two modes of mitosis intrigued the scientists in Dey's group at EMBL. In collaboration with Omaya Dudin from EPFL Lausanne, they chose to study Ichthyosporea, marine protists closely related to animals and fungi. Some species of these protists exhibit closed mitosis, while others adopt open mitosis.
The team discovered that
S. arctica favors closed mitosis and has a multinucleate stage, similar to many fungi and animal embryos, such as flies. Conversely,
C. perkinsii uses open mitosis and primarily has mononucleate stages.
These findings suggest that open mitosis, characteristic of animals, evolved hundreds of millions of years before the appearance of animals themselves. This provides new insights into the evolution of eukaryotic cell division mechanisms and their diversification in relation to the varied life cycles of organisms.
The research employed advanced techniques like ultrastructural expansion microscopy, allowing the study of the cell biology of Ichthyosporea. This interdisciplinary approach, combining comparative biology, electron microscopy, and comparative genomics, opens promising avenues for understanding the evolution of cell division.
The researchers continue their work under the PlanExM project, aiming to apply expansion microscopy to study the ultrastructural diversity of marine protists directly in environmental samples. These efforts are expected to shed more light on the diversity of life on Earth and the evolution of fundamental biological processes.