Cell division is crucial for growth, reproduction, and species survival in all living organisms. Despite having last shared a common ancestor over a billion years ago, animals and fungi, both belonging to the eukaryote group, differ in the way they carry out cell division. Animals undergo open mitosis, where the nuclear envelope breaks down, while fungi use closed mitosis, where the nuclear envelope remains intact. The factors influencing the evolution of these different modes of cell division have been the focus of research by the Dey Group at EMBL Heidelberg.
Through studying marine protists called Ichthyosporea, which are closely related to both animals and fungi, researchers found that different species within this group exhibit open or closed mitosis. The distinct cell division modes of Ichthyosporea provide insights into how organisms adapt to and use these processes. By examining two species of Ichthyosporeans, S. arctica and C. perkinsii, researchers discovered that S. arctica favours closed mitosis, similar to fungi, while C. perkinsii relies on open mitosis, more typical of animals. This sheds light on the evolutionary origins of open and closed mitosis.
The study utilized a combination of comparative phylogenetics, electron microscopy, ultrastructure expansion microscopy, comparative genomics, and mitotic spindle geometry and biophysics to unravel the mechanisms of cell division in Ichthyosporea. By analyzing the ultrastructure of the ichthyosporean cytoskeleton with ultrastructure expansion microscopy, researchers gained valuable insights into the biological processes of these lesser-known organisms. The study’s findings have implications for understanding how eukaryotic cell division mechanisms evolve and diversify.
The collaborative nature of the study highlighted the importance of exploring beyond traditional model organisms when tackling broad biological questions. The unique developmental patterns of Ichthyosporean species provide opportunities for comparative embryology studies, offering insights into the evolution of animals and shedding light on the diversity of life on Earth. The interdisciplinarity of the project not only advanced scientific understanding but also served as a testbed for collaborative research, showcasing the benefits of postdoctoral training through programmes like EIPOD at EMBL.
The research ongoing within the Dey, Dudin, and Schwab groups, such as the PlanExM project as part of the TREC expedition, aims to further explore the biodiversity of marine protists using expansion microscopy. By studying the ultrastructural diversity of marine protists directly in environmental samples, the research team hopes to uncover more about the diversity of life on Earth and the evolution of fundamental biological processes. The interdisciplinary approach and collaborative efforts within the groups continue to push the boundaries of scientific exploration and advance our understanding of life’s complexities.
