title: Notch and Hedgehog in the thymus/parathyroid common primordium: Crosstalk in organ formation.
abstract: The avian thymus and parathyroids (T/PT) common primordium derives from the endoderm of the third and fourth pharyngeal pouches (3/4PP). The molecular mechanisms that govern T/PT development are not fully understood. Here we study the effects of Notch and Hedgehog (Hh) signalling modulation during common primordium development using in vitro, in vivo and in ovo approaches. The impairment of Notch activity reduced Foxn1/thymus-fated and Gcm2/Pth/parathyroid-fated domains in the 3/4PP and further compromised the development of the parathyroid glands. When Hh signalling was abolished, we observed a reduction in the Gata3/Gcm2- and Lfng-expression domains at the median/anterior and median/posterior territories of the pouches, respectively. In contrast, the Foxn1 expression-domain at the dorsal tip of the pouches expanded ventrally into the Lfng-expression domain. This study offers novel evidence on the role of Notch signalling in T/PT common primordium development, in an Hh-dependent manner.
authors.affiliation: Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Piso 3, Ala C, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Electronic address: martafigueiredo@medicina.ulisboa.pt.
authors.forename: Marta
authors.initials: M
authors.lastname: Figueiredo
authors.affiliation: Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Piso 3, Ala C, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Electronic address: j.clarasilva@dundee.ac.uk.
authors.forename: Joana Clara
authors.initials: JC
authors.lastname: Silva
authors.affiliation: Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Piso 3, Ala C, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Electronic address: assantos@hikma.com.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Santos
authors.affiliation: Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Piso 3, Ala C, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Electronic address: vitorproa@medicina.ulisboa.pt.
authors.forename: Vitor
authors.initials: V
authors.lastname: Proa
authors.affiliation: Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Piso 3, Ala C, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Electronic address: halcobia@medicina.ulisboa.pt.
authors.forename: Isabel
authors.initials: I
authors.lastname: Alcobia
authors.affiliation: Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande C2, 1749-016 Lisboa, Portugal. Electronic address: rmzilhao@fc.ul.pt.
authors.forename: Rita
authors.initials: R
authors.lastname: Zilhão
authors.affiliation: Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Piso 3, Ala C, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Electronic address: a.cidadao@campus.ul.pt.
authors.forename: António
authors.initials: A
authors.lastname: Cidadão
authors.affiliation: Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Piso 3, Ala C, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Electronic address: helia.neves@campus.ul.pt.
authors.forename: Hélia
authors.initials: H
authors.lastname: Neves
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D002642:Chick Embryo; D003370:Coturnix; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins / Q000235:genetics / Q000502:physiology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D038081:Organogenesis / Q000235:genetics / Q000502:physiology; D010280:Parathyroid Glands / Q000196:embryology* / Q000502:physiology; D020239:Receptor Cross-Talk / Q000502:physiology; D051880:Receptors, Notch / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D013950:Thymus Gland / Q000196:embryology* / Q000502:physiology
chemical_list: D030161:Avian Proteins; D053823:Hedgehog Proteins; D051880:Receptors, Notch
keywords: Avian; Hedgehog; Notch; Pharyngeal pouches; Thymus/parathyroids common primordium