title: Trps1 is necessary for normal temporomandibular joint development.
abstract: Mutation of the human TRPS1 gene leads to trichorhinophalangeal syndrome (TRPS), which is characterized by an abnormal development of various organs including the craniofacial skeleton. Trps1 has recently been shown to be expressed in the jaw joints of zebrafish; however, whether Trps1 is expressed in the mammalian temporomandibular joint (TMJ), or whether it is necessary for TMJ development is unknown. We have analyzed (1) the expression pattern of Trps1 during TMJ development in mice and (2) TMJ development in Trps1 knockout animals. Trps1 is expressed in the maxillo-mandibular junction at embryonic day (E) 11.5. At E15.5, expression is restricted to the developing condylar cartilage and to the surrounding joint disc progenitor cells. In Trps1 knockout mice, the glenoid fossa of the temporal bone forms relatively normally but the condylar process is extremely small and the joint disc and cavities do not develop. The initiation of condyle formation is slightly delayed in the mutants at E14.5; however, at E18.5, the flattened chondrocyte layer is narrowed and most of the condylar chondrocytes exhibit precocious chondrocyte maturation. Expression of Runx2 and its target genes is expanded toward the condylar apex in the mutants. These observations underscore the indispensable role played by Trps1 in normal TMJ development in supporting the differentiation of disc and synoviocyte progenitor cells and in coordinating condylar chondrocyte differentiation.
authors.affiliation: Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
authors.forename: Ikumi
authors.initials: I
authors.lastname: Michikami
authors.forename: Toshiya
authors.initials: T
authors.lastname: Fukushi
authors.forename: Shiho
authors.initials: S
authors.lastname: Honma
authors.forename: Seisuke
authors.initials: S
authors.lastname: Yoshioka
authors.forename: Shunji
authors.initials: S
authors.lastname: Itoh
authors.forename: Yasuteru
authors.initials: Y
authors.lastname: Muragaki
authors.forename: Kojiro
authors.initials: K
authors.lastname: Kurisu
authors.forename: Takashi
authors.initials: T
authors.lastname: Ooshima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wakisaka
authors.forename: Makoto
authors.initials: M
authors.lastname: Abe
mesh_terms: D000818:Animals; D002356:Cartilage / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology; D019465:Craniofacial Abnormalities / Q000378:metabolism / Q000473:pathology; D050980:GATA Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008335:Mandibular Condyle / Q000378:metabolism / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics; D012097:Repressor Proteins; D013704:Temporomandibular Joint / Q000196:embryology* / Q000378:metabolism* / Q000473:pathology
chemical_list: D050980:GATA Transcription Factors; D012097:Repressor Proteins; C525953:Trps1 protein, mouse