title: Mesenchymal commitment to digital joint formation.
abstract: Temporal and spatial commitment of in vivo and in vitro mammalian digital joint development were characterized in a murine model. Alcian blue and alizarin red staining were used to label proteoglycans of cartilage matrix and mineralized matrix in both whole mounts and histological sections. Mesenchymal differentiation toward a joint fate was identified by a lack of matrix deposition in islands of joint precursor cells between phalangeal precursors, and localized lysosomal enzyme activity was later demonstrated in these regions during formation of the joint cavity. Organ-cultured forelimbs and in vivo specimens demonstrated analogous digital joint morphological trends. With a defined developmental window, reverse transcription, polymerase chain reaction, demonstrated differential gene expression of transforming growth factor-beta isotypes, aggrecan core protein, and type II collagen, suggesting a role for transforming growth factor-beta in directing digital joint development.
authors.affiliation: Department of Surgery, University of Southern California, Los Angeles, USA.
authors.forename: G T
authors.initials: GT
authors.lastname: Ginsburg
authors.forename: D
authors.initials: D
authors.lastname: Royster
authors.forename: G
authors.initials: G
authors.lastname: Kassabian
authors.forename: C F
authors.initials: CF
authors.lastname: Shuler
authors.forename: W R
authors.initials: WR
authors.lastname: Dougherty
authors.forename: A C
authors.initials: AC
authors.lastname: Sank
mesh_terms: D000199:Actins / Q000235:genetics / Q000502:physiology; D053674:Aggrecans; D000818:Animals; D001482:Base Composition / Q000235:genetics; D015519:Bone Density / Q000502:physiology*; D001857:Bone Matrix / Q000166:cytology; D002358:Cartilage, Articular / Q000166:cytology*; D002454:Cell Differentiation / Q000235:genetics; D003094:Collagen / Q000235:genetics / Q000502:physiology; D016326:Extracellular Matrix Proteins; D005260:Female; D005552:Forelimb / Q000166:cytology; D015870:Gene Expression / Q000502:physiology; D005865:Gestational Age; D066298:In Vitro Techniques; D007596:Joints / Q000166:cytology*; D037181:Lectins, C-Type; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000145:classification / Q000235:genetics / Q000502:physiology
chemical_list: C508320:Acan protein, mouse; D000199:Actins; D053674:Aggrecans; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D011509:Proteoglycans; D016212:Transforming Growth Factor beta; D003094:Collagen