Fibroblast growth factor receptor 4 (FGFR4) expression in newborn murine calvaria and primary osteoblast cultures.
Fibroblast growth factor receptor (FGFR) signalling is important in the initiation and regulation of osteogenesis. Although mutations in FGFR1, 2, and 3 genes are known to cause skeletal deformities, the expression of FGFR4 in bony tissue remains unclear. We have investigated the expression pattern of FGFR4 in the neonatal mouse calvaria and compared it to the expression pattern in cultures of primary osteoblasts. Immunohistochemistry demonstrated that FGFR4 was highly expressed in rudimentary membranous bone and strictly localised to the cellular components (osteoblasts) between the periosteal and endosteal layers. Cells in close proximity to the newly formed osteoid (preosteoblasts) also expressed FGFR4 on both the endosteal and periosteal surfaces. Immunocytochemical analysis of primary osteoblast cultures taken from the same cranial region also revealed high levels of FGFR4 expression, suggesting a similar pattern of cellular expression in vivo and in vitro. RT-PCR and Western blotting for FGFR4 confirmed its presence in primary osteoblast cultures. These results suggest that FGFR4 may be an important regulator of osteogenesis with involvement in preosteoblast proliferation and differentiation as well as osteoblast functioning during intramembranous ossification. The consistent expression of FGFR4 in vivo and in vitro supports the use of primary osteoblast cultures for elucidating the role of FGFR4 during osteogenesis.
School of Biomedical Sciences, Department of Anatomy and Developmental Biology, The University of Queensland, Brisbane, Australia. s.cool@uq.edu.au
Simon
S
Cool
Rebecca
R
Jackson
Paul
P
Pincus
Ian
I
Dickinson
Victor
V
Nurcombe
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D017931:DNA Primers / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D010006:Osteoblasts / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D051499:Receptor, Fibroblast Growth Factor, Type 4; D017468:Receptors, Fibroblast Growth Factor / Q000096:biosynthesis* / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D012886:Skull / Q000166:cytology*; D013997:Time Factors
D017931:DNA Primers; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; C496372:Fgfr4 protein, mouse; D051499:Receptor, Fibroblast Growth Factor, Type 4