Fig 1: Screening for a single clone with site-specific integration and the identification of its stem cell traits. (A) A single GFP-positive cell selected by flow cytometry was cultured to be a cell clone. (B) Southern blot identification of the site-specific integration event. (C) Expression analysis of the cell surface markers. The PE-conjugated antibodies (CD34, CD45, CD73, CD90 and CD105) were incubated with MSCs and then detected with flow cytometry. (D) Differentiation of the MSCs with site-specific integration into adipocytes, osteoblasts and chondrocytes was investigated by staining with Oil Red O, Alizarin red and Alcian blue, respectively. GFP, green fluorescent protein; MSCs, mesenchymal stem cells; C, wild-type MSC control group; T, MSCs with site-specific integration; P1/2, probe 1/2; PE, phycoerythrin; CD, cluster of differentiation.