Expression of an Olfactomedin-Related Gene in Rat Hair Follicular Papilla Cells

The study identified FP-1 as a highly specific gene expressed in rat follicular papilla (FP) cells, but not in dermal fibroblasts or most other tissues. FP-1 encodes a 549 amino acid protein with a signal peptide, collagen repeats, and an olfactomedin-like domain. This protein, detected as a 72 kDa glycoprotein, is expressed in a hair cycle-dependent manner, being present during the anagen phase but not in catagen or telogen phases. FP-1 is likely an extracellular matrix protein crucial for FP organization during hair growth.