title: Avian hairy gene expression identifies a molecular clock linked to vertebrate segmentation and somitogenesis.
abstract: We have identified and characterized c-hairy1, an avian homolog of the Drosophila segmentation gene, hairy. c-hairy1 is strongly expressed in the presomitic mesoderm, where its mRNA exhibits cyclic waves of expression whose temporal periodicity corresponds to the formation time of one somite (90 min). The apparent movement of these waves is due to coordinated pulses of c-hairy1 expression, not to cell displacement along the anteroposterior axis, nor to propagation of an activating signal. Rather, the rhythmic c-hairy mRNA expression is an autonomous property of the paraxial mesoderm. These results provide molecular evidence for a developmental clock linked to segmentation and somitogenesis of the paraxial mesoderm, and support the possibility that segmentation mechanisms used by invertebrates and vertebrates have been conserved.
authors.affiliation: Institut d'Embryologie Cellulaire et Moléculaire du Centre National de la Recherche Scientifique et du Collège de France, Nogent sur Marne.
authors.forename: I
authors.initials: I
authors.lastname: Palmeirim
authors.forename: D
authors.initials: D
authors.lastname: Henrique
authors.forename: D
authors.initials: D
authors.lastname: Ish-Horowicz
authors.forename: O
authors.initials: O
authors.lastname: Pourquié
mesh_terms: D000818:Animals; D030161:Avian Proteins; D051792:Basic Helix-Loop-Helix Proteins; D001683:Biological Clocks / Q000235:genetics*; D002465:Cell Movement / Q000235:genetics; D002642:Chick Embryo; D003513:Cycloheximide; D004330:Drosophila / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D008969:Molecular Sequence Data; D010507:Periodicity; D011500:Protein Synthesis Inhibitors; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D019170:Somites / Q000166:cytology / Q000502:physiology*; D014714:Vertebrates
chemical_list: D030161:Avian Proteins; D051792:Basic Helix-Loop-Helix Proteins; D003513:Cycloheximide; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D012333:RNA, Messenger; C109424:hairy1 protein, Gallus gallus