Fig. 2. PTN and SDF-1 are expressed by dermal fibroblasts in vivo. (A) Dermis and epidermis of mouse back skin were dissected and semi-quantitative RT-PCR was performed to reveal the expression of Ptn and SDF-1 in the dermal compartment. Keratin 10 (K10) and procollagen type I, 2 (Col1a2) were used as controls for the separation. The cDNA was standardized to Hprt levels. (B) In situ hybridization using DIG-labelled riboprobes for Ptn and Sdf-1 confirmed dermal fibroblasts as a source of cytokine expression. Hybridization was visualized using diaminobenzidine (DAB, reddish-brown signal) and nuclei were counterstained with Hematoxylin.