Understanding where we come from can reveal how life itself evolved to its stunning complexity. The study delves into the origins of the cells that make healing, growth and regeneration possible in animals: stem cells. By tracing the surprising roots of a key protein to ancient single-cell organisms, the study reveals a story that links humans to their earliest ancestors, revealing how the building blocks of life evolved long before animals appeared on Earth.
Scientists have long wondered about the origins of multicellular animals and how their cells developed such a wide range of forms and functions. A new study led by Professor Ralf Jauch, Dr Alex de Mendoza and colleagues from the University of Hong Kong and the Max Planck Institute for Terrestrial Microbiology reveals the history of Sox and POU proteins that are essential for the function of microorganisms . The study, published in Nature Communications, challenges previous assumptions that these proteins only occur in animals.
The results of this study indicate that Sox and POU proteins were present in the single-celled ancestors of animals. These proteins are found in choanoflagellates, single-celled organisms closely related to animals. Remarkably, the Sox proteins in these organisms were found to be similar to the mammalian versions, specifically Sox2, and could even transform mouse somatic cells into cells capable of developing into any type of specialized cell. However, POU proteins from these organisms, although structurally similar, lack the characteristics required for such transformation.
Experts in the field may find the lead researcher’s comments compelling. Professor Jauch explains: “Our results suggest that the evolution of animal stem cells may have involved the adaptation of a pre-existing set of transcription factors.” This means that the properties of Sox proteins from ancient organisms may have made them suitable for early animal stem cell processes.
Advanced techniques allow researchers to reconstruct ancient versions of Sox proteins and test their capabilities. These experiments suggest that such proteins can induce somatic cells in modern animals to transform into pluripotent stem cells. This suggests that the tools needed to create stem cells existed long before animals existed, potentially making the transition to multicellular life more feasible.
Going forward, the implications of this work expand our understanding of how cellular diversity and complexity evolve. The researchers emphasize that these proteins are refined over time and play a crucial role in helping cells maintain their ability to renew themselves and transform into specialized forms. Their study also identified gaps in earlier studies that may have underestimated how widespread these proteins were among ancient single-celled animal relatives.
Ultimately, this study provides strong evidence that Sox and POU proteins were key players in animal stem cell development even before multicellular organisms existed. It connects an important missing piece of the evolutionary story and lays the foundation for further research into the mechanisms that helped life transition from simple to complex forms.
Journal reference
Gao, Y., Tan, D.S., Gilbig, M., et al. “The emergence of Sox and POU transcription factors predates the origin of animal stem cells.” Nature Communications (2024). DOI: https://doi.org/10.1038/s41467-024-54152-x
About the author
Professor Ralph Rauch is a distinguished scientist specializing in stem cell biology and transcriptional regulation. Working at the University of Hong Kong, he is a leader in uncovering the molecular mechanisms that drive cell identity and pluripotency. His work focuses on transcription factors such as Sox and POU proteins, which play critical roles in stem cell maintenance and differentiation. Professor Jauch works to understand the evolutionary origins of these factors, bridging the fields of molecular biology and evolutionary science. His innovative research uses state-of-the-art techniques to reconstruct ancient proteins, revealing how cellular complexity emerged during evolution. Widely respected for his scientific rigor, he actively collaborates with researchers around the world and mentors the next generation of scientists. Through his groundbreaking research, Professor Jauch continues to make significant contributions to stem cell biology and our understanding of the earliest molecular basis of life.
Dr. Alex de Mendoza is a renowned evolutionary biologist whose research explores the molecular origins of complex life forms. He is affiliated with Queen Mary University of London and works on decoding how early transcription factors such as Sox and POU contribute to the evolution of multicellular organisms. Dr. de Mendoza’s work combines evolutionary theory with cutting-edge molecular biology, allowing him to uncover the ancient genetic mechanisms that shape the diversity of life. His research delves into how single-cell ancestors laid the foundation for animal stem cells, revealing fascinating connections between ancient proteins and modern biology. Dr. de Mendoza is known for his interdisciplinary approach, collaborating with scientists around the world to address fundamental questions about the evolution of life. Through his research, teaching, and scientific outreach, he continues to inspire curiosity about the origins of multicellularity and the molecular pathways that connect ancient life to today’s biological systems.
