title: A molecular clock operates during chick autopod proximal-distal outgrowth.
abstract: Temporal control can be considered the fourth dimension in embryonic development. The identification of the somitogenesis molecular clock provided new insight into how embryonic cells measure time. We provide the first evidence of a molecular clock operating during chick fore-limb autopod outgrowth and patterning, by showing that the expression of the somitogenesis clock component hairy2 cycles in autopod chondrogenic precursor cells with a 6 h periodicity. We determined the length of time required to form an autopod skeletal limb element, and established a correlation between the latter and the periodicity of cyclic hairy2 gene expression. We suggest that temporal control exerted by cyclic gene expression can be a widespread mechanism providing cellular temporal information during vertebrate embryonic development.
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Pascoal
authors.forename: Cláudia R
authors.initials: CR
authors.lastname: Carvalho
authors.forename: Joaquín
authors.initials: J
authors.lastname: Rodriguez-León
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Delfini
authors.forename: Delphine
authors.initials: D
authors.lastname: Duprez
authors.forename: Sólveig
authors.initials: S
authors.lastname: Thorsteinsdóttir
authors.forename: Isabel
authors.initials: I
authors.lastname: Palmeirim
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000235:genetics / Q000378:metabolism; D001683:Biological Clocks; D019521:Body Patterning; D002642:Chick Embryo; D047108:Embryonic Development; D005552:Forelimb / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D008648:Mesoderm / Q000378:metabolism; D010507:Periodicity
chemical_list: D030161:Avian Proteins