Présentation
Department of Developmental and Stem Cell Biology
2017 Seminar Series
Friday 7th April — at 12.00 pm @ Amphi Jacques Monod (Bât.66)
SEMINAR ” Left-Right asymmetry in Drosophila: from molecular to organism chirality “
Invited Speaker ⇒ Stéphane Noselli
IBV – Institut of Biology Valrose
CNRS UMR7277, Inserm U1091, Sophia-Antipolis – France
Abstract : Breaking Left-Right (LR) symmetry in Bilateria embryos is a major event in body plan organization. Establishment of LR asymmetry is essential for body handedness, directional looping of internal organs (heart, gut…) and differentiation of the heart and brain. Many syndromes and defects are associated with aberrant LR asymmetry in human. We have characterized the LR body axis in Drosophila through the identification of myosin ID (myoID) as a unique situs inversus gene. MyoID is a major LR determinant in flies that is required for dextral coiling of organs (genitalia, hindgut, testis). In the absence of myoID, flies show an inverted phenotype with organs undergoing sinistral morphogenesis. Our recent work revealed a direct coupling between the LR determinant MyoID and the atypical cadherin Dachsous for propagation of LR information to target tissues, providing the first evidence for a role of the Fat/Ds PCP pathway in LR asymmetry. Our ongoing work aims at addressing the following questions: i) what is the molecular and cellular function of myoID, ii) what is the nature of chirality and how does this property crosses multiple scales (from molecular to organismal), and, iii) what is the evolutionary conservation of myoID function in vertebrates (zebrafish, xenopus) LR asymmetry? We will present novel results showing that myoID is not only necessary for establishing LR asymmetry but is also sufficient to generate de novo LR asymmetry, making it a true LR determinant. Furthermore, molecular studies show that MyoID interaction with actin is chiral, and that its function is conserved in vertebrates. Altogether, our results reveal that the MyoID system is a major chirality determinant essential for orienting the LR axis in both vertebrates and invertebrates.
Hosted by Sigolène Meilhac