title: Patterning in time and space: HoxB cluster gene expression in the developing chick embryo.
abstract: The developing embryo is a paradigmatic model to study molecular mechanisms of time control in Biology. Hox genes are key players in the specification of tissue identity during embryo development and their expression is under strict temporal regulation. However, the molecular mechanisms underlying timely Hox activation in the early embryo remain unknown. This is hindered by the lack of a rigorous temporal framework of sequential Hox expression within a single cluster. Herein, a thorough characterization of HoxB cluster gene expression was performed over time and space in the early chick embryo. Clear temporal collinearity of HoxB cluster gene expression activation was observed. Spatial collinearity of HoxB expression was evidenced in different stages of development and in multiple tissues. Using embryo explant cultures we showed that HoxB2 is cyclically expressed in the rostral presomitic mesoderm with the same periodicity as somite formation, suggesting a link between timely tissue specification and somite formation. We foresee that the molecular framework herein provided will facilitate experimental approaches aimed at identifying the regulatory mechanisms underlying Hox expression in Time and Space.
authors.affiliation: a Life and Health Sciences Research Institute (ICVS); School of Health Sciences , University of Minho ; Braga , Portugal.
authors.forename: Analuce
authors.initials: A
authors.lastname: Gouveia
authors.forename: Hugo M
authors.initials: HM
authors.lastname: Marcelino
authors.forename: Lisa
authors.initials: L
authors.lastname: Gonçalves
authors.forename: Isabel
authors.initials: I
authors.lastname: Palmeirim
authors.forename: Raquel P
authors.initials: RP
authors.lastname: Andrade
mesh_terms: D000818:Animals; D002642:Chick Embryo / Q000166:cytology / Q000378:metabolism; D002645:Chickens; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D008648:Mesoderm / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins
keywords: A-P, anterior-posterior; HH, Hamburger and Hamilton; Hox code; Hox genes; PSM, presomitic mesoderm; chick embryo; nc, notochord; nt, neural tube; ps, primitive streak; spatial collinearity; temporal collinearity; temporal control