The origins of asymmetry : A protein that makes you do the twist

Paris, 22 November 2018 Asymmetry plays a major role in biology at every scale: think of DNA spirals, the fact that the human heart is positioned on the left, our preference to use our left or right hand … A team from the Institute of biology Valrose (CNRS/Inserm/Université Côte d'Azur), in collaboration with colleagues from the University of Pennsylvania, has shown how a single protein induces a spiral motion in another molecule. Through a domino effect, this causes cells, organs, and indeed the entire body to twist, triggering lateralized behaviour. This research is published in the journal Science on November 23, 2018. Our world is fundamentally asymmetrical: think of the double helix of DNA, the asymmetrical division of stem cells, or the fact that the human heart is positioned on the left … But how do these asymmetries emerge, and are they linked to one another? At the Institute of biology Valrose, the team led by the CNRS researcher Stéphane Noselli, which also includes Inserm and Université Cote d'Azur researchers, has been studying right–left asymmetry for several years in order to solve these enigmas. The biologists had identified the first gene controlling asymmetry in the common fruit fly (Drosophila), one of the biologists' favoured model organisms. More recently, the team showed that this gene plays the same role in vertebrates: the protein that it produces, Myosin 1D, ¹ controls the coiling or rotation of organs in the same direction. In this new study, the researchers induced the production of Myosin 1D in the normally symmetrical organs of Drosophila, such as the respiratory trachea.