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Tenascin‐C is associated with early stages of chondrogenesis by chick mandibular ectomesenchymal cells in vivo and in vitro
Author(s) -
Gluhak Jelica,
Mais Akis,
Mina Mina
Publication year - 1996
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/(sici)1097-0177(199601)205:1<24::aid-aja3>3.0.co;2-7
Subject(s) - chondrogenesis , aggrecan , tenascin c , biology , cartilage , tenascin , mesenchyme , in situ hybridization , extracellular matrix , microbiology and biotechnology , messenger rna , mesenchymal stem cell , anatomy , biochemistry , fibronectin , pathology , osteoarthritis , gene , medicine , alternative medicine , articular cartilage
Tenascin‐C is an extracellular matrix protein thought to be involved in skeletogenesis. Wehave examined the distribution of tenascin‐C in the developing chick mandibular arch betweenstages 18–36, and during in vitro chondrogenesis of mandibular ectomesenchymal cellsin micromass cultures using a probe and antibody that correspond to the portion of the tenascin‐Ctranscript conserved in all of the three known chick splice variants. In situ hybridization andimmunohistochemical analyses demonstrate that tenascin‐C is predominantly expressed in thecondensing mesenchyme of developing cartilage, and in the perichondrium of differentiatedcartilage. Tenascin‐C expression, although detected in differentiating chondroblasts, was notdetected in differentiated cartilage. Tenascin‐C was also expressed in the developing membranousbones. In addition, the expression of tenascin‐C transcripts during in vitro chondrogenesis ofmandibular ectomesenchymal cells in micromass cultures was compared to the patterns ofexpression of aggrecan core protein and α1(I) collagen transcripts. Our in situ hybridizationanalyses of micromass cultures demonstrate the expression of tenascin‐C and agreecan coreprotein mRNAs by pre‐chondrogenic aggregates in the 1‐day cultures and by chondroblasts indifferentiating cartilage nodules in 2‐day cultures. In 4‐ and 9‐day cultures, the pattern ofexpression of tenascin‐C mRNA was different from the patterns of expression of aggrecan coreprotein mRNA, and appeared to be more closely related to the expression of α1(I) collagenmRNA. Aggrecan core protein mRNA was expressed by chondrocytes in cartilage nodules in 4‐and 9‐day cultures. On the other hand, tenascin‐C and α1(I) collagen mRNAs, in additionto being expressed in the loose connective tissues in the inter‐nodular spaces, were predominantlyexpressed by the elongated, flattened, and fibroblast‐like cells around the cartilage nodules. Theseresults indicate that during the in vitro chondrogenesis of mandibular ectomesenchymal cells,expression of tenascin‐C mRNA identifies chondrocytes in their early stages of differentiation.The patterns of expression of tenascin‐C mRNA in 4‐ and 9‐day cultures further suggest thattenascin‐C is expressed in the perichondrium‐like structures that form around the cartilage nodulesin micromass cultures. Therefore, our in vitro studies, in agreement with our in vivo studies,suggest an association of tenascin‐C with the initial or early stages of chondrogenesis in thechicken mandibular arch. © 1996 Wiley‐Liss, Inc.