title: An immunohistochemistry study of Sox9, Runx2, and Osterix expression in the mandibular cartilages of newborn mouse.
abstract: The purpose of this study is to investigate the spacial expression pattern and functional significance of three key transcription factors related to bone and cartilage formation, namely, Sox9, Runx2, and Osterix in cartilages during the late development of mouse mandible. Immunohistochemical examinations of Sox9, Runx2, and Osterix were conducted in the mandibular cartilages of the 15 neonatal C57BL/6N mice. In secondary cartilages, both Sox9 and Runx2 were weakly expressed in the polymorphic cell zone, strongly expressed in the flattened cell zone and throughout the entire hypertrophic cell zone. Similarly, both transcriptional factors were weakly expressed in the uncalcified Meckel's cartilage while strongly expressed in the rostral cartilage. Meanwhile, Osterix was at an extremely low level in cells of the flattened cell zone and the upper hypertrophic cell zone in secondary cartilages. Surprisingly, Osterix was intensely expressed in hypertrophic chondrocytes in the center of the uncalcified Meckel's cartilage while moderately expressed in part of hypertrophic chondrocytes in the rostral process. Consequently, it is suggested that Sox9 is a main and unique positive regulator in the hypertrophic differentiation process of mandibular secondary cartilages, in addition to Runx2. Furthermore, Osterix is likely responsible for phenotypic conversion of Meckel's chondrocytes during its degeneration.
authors.affiliation: Department of Orthodontics, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou 510055, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Zhao
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Weiwei
authors.initials: W
authors.lastname: Chen
authors.forename: Xinli
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002356:Cartilage / Q000166:cytology / Q000378:metabolism*; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism*; D007150:Immunohistochemistry; D008334:Mandible / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000378:metabolism*; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C493716:Runx2 protein, mouse; D055758:SOX9 Transcription Factor; C527933:Sox9 protein, mouse; D000076182:Sp7 Transcription Factor; C479466:Sp7 protein, mouse; D014157:Transcription Factors