Culture of ovine keratinocytes : An experimental model for wool growth

Wool fibres are formed from the germinative epithelium, a population of keratinocytes at the base of wool follicles. In order to test the function of candidate wool growth genes and pharmaceuticals, we have developed methods to isolate and maintain these cells in culture. Pure, clonal lines of ovine keratinocytes were isolated from both vibrissae and wool follicles. Vibrissa-derived cells proliferated more extensively before senescing, but cells from both follicle types possessed ample proliferative potential for further experimentation. Standard assays have been established to quantify keratinocyte proliferation and apoptosis in culture. Differentiation of keratinocytes could be induced by maintaining them at high density for a week. Keratinocytes expressed differentiation markers for epidermis and inner root sheath. Expression of a chosen gene could be up-regulated by transfection with a liposome-borne plasmid. A transfected plasmid encoding a fluorescent reporter protein was expressed in 68-100% of cells. Similarly, expression of a gene of interest could be suppressed by RNA interference. The experimental tractability of these keratinocytes suggests that they will be a valuable model for investigating the cell biology and molecular genetics of wool growth. The methods described form a unique experimental system to identify leads for new technologies that improve