title: Critical behavior and axis defining symmetry breaking in Hydra embryonic development.
abstract: The formation of a hollow cellular sphere is often one of the first steps of multicellular embryonic development. In the case of Hydra, the sphere breaks its initial symmetry to form a foot-head axis. During this process a gene, ks1, is increasingly expressed in localized cell domains whose size distribution becomes scale-free at the axis-locking moment. We show that a physical model based solely on the production and exchange of ks1-promoting factors among neighboring cells robustly reproduces the scaling behavior as well as the experimentally observed spontaneous and temperature-directed symmetry breaking.
authors.affiliation: Politecnico di Torino and CNISM, 10129 Torino, Italy. andrea.gamba@polito.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Gamba
authors.forename: Mario
authors.initials: M
authors.lastname: Nicodemi
authors.forename: Jordi
authors.initials: J
authors.lastname: Soriano
authors.forename: Albrecht
authors.initials: A
authors.lastname: Ott
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian; D006829:Hydra / Q000033:anatomy & histology / Q000196:embryology*; D008954:Models, Biological