title: The proto-oncogene C-raf-1 is highly expressed only in the hypertrophic zone of the growth plate.
abstract: Proto-oncogene c-raf-1, the cellular homologue of the acutely transforming oncogene v-raf, has a central role in the signal transduction pathways. The growth plate, due to its non-overlapping zones of chondrocyte maturation, provides a physiological in situ model for investigating the role of c-raf-1 in proliferation and differentiation of chondrocytes. In this study, Northern blotting was first performed to examine the expression of mRNA for c-raf-1 in the embryonic chick tibial growth plate. It revealed that the normal levels of c-raf-1 mRNA were associated with the whole growth plate. We then investigated the localization of c-raf-1 mRNA and c-raf-1 protein in the growth plate by in situ hybridization and immunohistochemistry in order to determine whether c-raf-1 is involved in chondrocyte maturation. Our results showed that c-raf-1 mRNA and c-raf-1 protein were detected only in the hypertrophic zone. The data suggest involvement of this proto-oncogene in chondrocyte differentiation and/or hypertrophy rather than in proliferation.
authors.affiliation: Department of Oral Surgery, School of Medicine, Chiba University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kaneko
authors.forename: H
authors.initials: H
authors.lastname: Tanzawa
authors.forename: K
authors.initials: K
authors.lastname: Sato
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002454:Cell Differentiation; D002455:Cell Division; D002642:Chick Embryo; D006132:Growth Plate / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D016612:Paraffin Embedding; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D019908:Proto-Oncogene Proteins c-raf; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013977:Tibia; D016610:Tissue Embedding
chemical_list: D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf