More than half of our genetic material is made up of thousands of remnants from ancient viral DNA, known as transposable elements. These remnants are found across a vast range of life forms. Once regarded as the “dark side” of our genetic makeup, studies conducted by researchers from Helmholtz Munich and Ludwig-Maximilians-Universität (LMU) have uncovered their vital role in the development of early embryos.
Questions About Ancient Viral DNA’s Functionality
Transposable elements, which are remnants of ancient viral DNA, become active in the initial hours and days post-fertilization. This early stage of embryonic development is marked by incredible flexibility in embryonic cells, yet the mechanisms and factors that govern this adaptability are still not fully understood. Studies using models like mice indicate that transposable elements could be essential for cellular flexibility, but it remains unclear if this is a common trait among all mammals. Given their varied evolutionary backgrounds, questions about how these viral remnants are preserved in mammalian genomes persist. Gaining insights into the mechanisms that regulate the activation of transposable elements is critical for enhancing reproductive medicine and clarifying the fundamental aspects of genome regulation.
Reactived Viral Elements in Mammalian Embryos
A research team, led by Prof. Maria-Elena Torres-Padilla from Helmholtz Munich and LMU, aimed to investigate these ancient DNA sequences by creating a new method to analyze their gene expression. They compiled a single-embryo atlas by analyzing embryos from various mammalian species, including mice, cows, pigs, rabbits, and rhesus macaques. Their research yielded unexpected results: They found that some very old viral elements, previously thought to be extinct, are actually active in mammalian embryos, and each species exhibits unique types of these elements.
New Opportunities for Genetic Research and Cell Flexibility
These findings demonstrate that the activation of transposable elements is preserved across different species. Identifying these specific elements opens up exciting possibilities for manipulating thousands of genes simultaneously in cells. “This method represents a fresh strategy to influence cell destinies, like steering stem cell differentiation, which usually involves the simultaneous alteration of countless genes,” explains co-first author Dr. Marlies Oomen. “Our research underlines the importance of grasping the regulatory frameworks surrounding transposable elements.”
Prof. Torres-Padilla adds, “Our study revealed that the activation of transposable elements is a unique characteristic of early embryos in several mammalian species. This is crucial since these early-stage cells can evolve into all types of body cells. By learning how these cells manage ancient viral elements, we gain valuable insights into cellular flexibility. This research opens doors for future studies into specific regulatory elements, significantly impacting health, disease, and the potential effects of manipulating these elements on cellular functions.”
A Comprehensive Dataset for Early Development Study Across Mammals
Alongside their innovative approach that creates new pathways for researchers examining single cells and embryos, this study has produced an extraordinary collection of data. Early embryo development is a rapidly changing process that captivates scientists, but most research typically concentrates on one species, usually mouse or human. In contrast, this study adopted an evolutionary perspective by comparing multiple mammalian species, facilitating the identification of critical regulatory pathways common among mammals. The biological knowledge acquired from this research, combined with the extensive dataset, will serve as a rich resource for those studying developmental and reproductive biology.
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About the Researchers
Prof. Maria-Elena Torres-Padilla is the Director of the Institute of Epigenetics and Stem Cells at Helmholtz Munich and a professor at the Faculty of Biology at Ludwig-Maximilians-Universität (LMU).
Dr. Marlies Oomen is a Postdoctoral Researcher at the Institute of Epigenetics and Stem Cells at Helmholtz Munich.
