Figure 4:

RTL3 over expression enhances SOX-9 and COL2A1 expression in human chondrocytes. Over expression of RTL3 enhanced RTL3 mRNA (A) and (B) protein without adverse effects to cell viability (C). RTL3 over expression rescued SOX-9 (D) and expression COL2A1 (E) mRNA expression and protein levels (F). RTL3 over expression also enhanced COL2A1 promoter reporter activity in a dose-dependent manner (G). Over expression of SOX-9 successfully enhanced SOX-9 mRNA (H) and protein (K) levels in transfected chondrocytes without adverse effects to cell viability (I). Surprisingly, expression of RTL3 mRNA (J) and protein (K) levels were also increased in pSOX-9 treated cells. When chondrocytes were transfected with pSOX-9 over expression plasmid as well as treated with siRNA-depletion of RTL3, the -COL2A1 promoter reporter activity failed to elicit the same robust activity (L).