Fig. 2.

CircPOK and Pokemon protein play antithetical functions in mesenchymal tumors. a Expression of LinPOK and circPOK in human primary undifferentiated sarcoma samples (n = 10) compared to normal fibrous tissue (bar = 1, n = 6), and in human primary osteosarcoma (n = 17) compared to normal human osteoblasts (bar = 1, n = 1). b Schematic representation of the Zbtb7a^F/F locus, and deletion of Pokemon protein and circPOK in the MSCs isolated from these mice, upon transduction with CRE-expressing vector. c Schematic representation of vectors used to express circPOK or cDNA-POK is shown on the left, along with the control vectors. Expression of circPOK-GFP, circGFP or LinPOK in all the conditions is shown in the charts on the right. d On the left, schematic representation of the strategy used to generate p53^−/−Zbtb7a_Ex2^F/F-CRE MSCs, which are null for the expression of both Pokemon-protein and circPOK, and to “add-back” specifically the protein or circPOK. The chart on the right show the expression of LinPOK or circPOK upon experiments of “adding-back” in null cells (CRE), compared to the endogenous expression of LinPOK and circPOK in wild-type MSCs (CTR). e Schematic representation of the in vivo tumorigenesis assays is depicted on the left; the chart in the middle represents the relative size of the tumors generated by p53^−/−Zbtb7a_Ex2^F/F-CRE MSCs expressing the following vectors: the empty vector, circGFP, cDNA POK-GFP, circPOK and circPOK-SDmut. Representative pictures of the tumor sections stained with H&E and Ki-67 are shown on the right