The vascular permeability assay was performed as described elsewhere (1). Seven-week-old K14-AGF (angiopoietin-related growth factor) mice and their controls were anesthetized, and 100 m l of 1% Evans blue dye (Sigma) was injected into tail vein. Extravasation of Evans blue dye was recorded at 30 min after injection. Subsequently, mouse was perfused from the left ventricle with 1% paraformaldehyde in citrate buffer at pH 3.5. Ears were removed, gently blotted, and weighed, and Evans blue dye was extracted from ears with 1 ml of formamide. The amount of extravasated dye was measured with a spectrophotometer (610 nm) and expressed as the content of dye per 1 mg wet weight of tissue. Each experiment was performed in triplicate and repeated three times.

Cell sorting and culture of primary keratinocytes. Primary epidermal keratinocytes from both whole skin of 5-day-old K14-AGF mice and controls were prepared by treatment with 2.4 units/ml Dispase (GIBCO/BRL, Grand Island, NY) and by passing the tissues through a 23 G needle. Cells were stained with fluorescein isothiocyanate (FITC)-conjugated anti-b 1-integrin antibody (Ha2/5, Pharmingen) and analyzed and sorted by FACSVantage to obtain b 1-integrinpositive cells. Sorted cells (2 ´ 10³) were cultured on primary embryonic fibroblast cells in a 24-well dish in Keratinocyte Growth Medium-2 (KGM-2; BioWhittaker, Walkersville, MD) for 6 days. Cells were stained with anti- mouse keratin14 (K14) antibody (Covance) and several stained colonies were counted. All experiments were performed in triplicate.

1. Elson, D. A., Thurston, G., Huang, L. E., Ginzinger, D. G., McDonald, D. M., Johnson, R. S. & Arbeit, J. M. (2001) Genes Dev. 15, 2520-2523.