Proximal promoters and overlapping binding regions for Sp1 and Egr-1. Proximal promoters of rat type II collagen and aggrecan, but not of link protein, have overlapping binding regions for Sp1 and Egr-1. Upstream regions of (a) the rat type II collagen, (b) aggrecan and (c) link protein were analysed by TRANSFAC  for transcription factor binding sites. (a) and (b) Proximal to the transcriptional start site, the type II collagen and aggrecan promoters have multiple putative Sp1 (underlined) and Egr-1 binding sites (bold), some of which are found in overlapping regions.
Rockel et al. Arthritis Research & Therapy 2009 11:R8 doi:10.1186/ar2595