Primary chondrocyte-enriched cells from littermate wild-type C57BL/6mice were transfected with pcDNA-NICD (NICD, full circles) to induce NICD or with control pcDNA3.1 (pcDNA, empty circles). Cells were co-transfected with the pGL3 luciferase expression vector, the 12-CSL-Luc reporter (12xCSL) or a fragment of the Il6 promoter cloned in pGL3 (Il6-Luc), and a β-galactosidase expression vector. Chondrocytes were harvested after 48 h. Data are expressed as luciferase activity corrected for β-galactosidase activity, relative to corrected luciferase activity in control cells transfected with pGL3. Observations represent cultures from individual mice n = 6. * indicates differences between NICD and pcDNA. # indicates a difference between 12xCSL, or Il6-Luc, and pGL3 activity in cells transfected with pcDNA. + indicates a difference between 12xCSL, or Il6-Luc, and pGL3 activity in cells transfected with NICD.