Fig. 1From: Gene expression analysis of skin grafts and cultured keratinocytes using synthetic RNA normalization reveals insights into differentiation and growth controlSample collection. a Split-thickness skin graft (SG) samples were harvested in the operating room using a dermatome. Lower panel shows a haematoxylin-eosin stained section of SG sample demonstrating minimal dermis involvement (light blue tissue). b Full thickness biopsy samples were collected as 3Â mm punch biopsies. Red dotted line in the schematic drawing of skin (middle panel) demonstrates sampling depth for SG samples (upper line) and punch biopsy samples (lower line). Keratinocyte (KC) cultures were established from punch biopsy samples after enzymatic dissociation, and isolated primary KC were cultured to the passage 1 (EKC samples) and to the passage 5/6 (LKC samples). c The spontaneously immortalized model keratinocyte cell line, HaCaT, was used as a cell line model. Total RNA was isolated from each sample as outlined in Materials and MethodsBack to article page