Identification of a novel fibroblast growth factor, FGF-22, preferentiallyexpressed in the inner root sheath of the hair follicle

We isolated cDNA encoding a novel fibroblast growth factor (FGF-22) (170 am ino acids) from human placenta. Of the FGF family members, FGF-22, which ap pears to be a secreted protein, is most similar to FGF-IO and FGF-7 ( simil ar to 46% and similar to 40% amino acid identities, respectively). The huma n FGF-22 gene was localized on chromosome 19p13.3. We also isolated mouse c DNA encoding FGF-22 (162 amino acids) from the skin. Mouse FGF-22 shows hig h homology (87% amino acid identity) to human FGF-22. Mouse FGF-22 mRNA was found to be preferentially expressed in the skin among the mouse adult tis sues examined by Northern blotting analysis. By in situ hybridization, FGF- 22 mRNA in the skin was found to be preferentially expressed in the inner r oot sheath of the hair follicle. Therefore, FGF-22 is expected to be a uniq ue FGF that plays a role in hair development. (C) 2001 Elsevier Science B.V . All rights reserved.