Fibroblast growth factor signalling in the hair growth cycle: Expression of the fibroblast growth factor receptor and ligand genes in the murine hair follicle

✍ Scribed by Thomas A. Rosenquist; Gail R. Martin

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 1006 KB
• Volume: 205
• Category: Article
• ISSN: 1058-8388
• DOI: 10.1002/(sici)1097-0177(199604)205:4<379::aid-aja2>3.0.co;2-f

✦ Synopsis

Using RNA in situ hybridization analysis, we have characterized the expression domains of the four known members of the FGF receptor-tyrosine kinase gene family in the murine hair follicle at various stages of the hair growth cycle. During anagen, we detected FgFl RNA in the dermal papilla, FgFZ RNA in hair matrix cells near the dermal papilla, FgF3 RNA in pre-cuticle cells in the periphery of the hair bulb, and F@4 RNA in cells in the periphery of the hair bulb and also in the inner and outer root sheath in the lower half of the follicle neck. No RNA exprcssion of these genes was detected during late catagen or telogen. We have previously shown that FBfs is expressed in the outer root sheath in the transient portion of the follicle (Hebert et al. [19941 Cell 781017-1025). In the present study we have also assayed for the expression of six other members of the FGF ligand gene family, Fgf3, Fgfa, F m , F N 7 F m , and F@. Among these FGF genes, only Fgf7 was found to be expressed in the hair follicle. Fgf7 RNA is localized to the dermal papilla during anagen, but expression is downregulated by the late-anagen VI stage. We have also demonstrated that addition of FGF5 protein to the culture medium changes the behavior of dermal papilla cells in vitro, indicating that they are capable of responding to FGF5. Together with previously published data, these results provide a complete analysis of FGF ligand and FGF receptor-tyrosine kinase gene expression in the hair follicle, and suggest that FGF signalling may have several functions in the hair growth cycle.