SOX9 Is an Activator and Repressor in Chondrocytes Figure 6. GLI as SOX9 partner in Col10a1 repression. (A) ChIP assays with CCL cells (upper panel) and E13.5 mouse limbs (lower panel) using various antibodies. The products were amplified with primers for element A of Col10a1 or enhancer element of Col2a1 in intron 1. Extract was immunoprecipitated with rabbit IgG or without antibody (2) as negative reference. Extract was directly used in PCR as positive control (input). (B) The PLoS Genetics | www.plosgenetics.org 10 November 2011 | Volume 7 | Issue 11 | e1002356