First Author | Roca H | Year | 2008 |
Journal | Nucleic Acids Res | Volume | 36 |
Issue | 5 | Pages | 1723-30 |
PubMed ID | 18263612 | Mgi Jnum | J:172158 |
Mgi Id | MGI:5004771 | Doi | 10.1093/nar/gkn022 |
Citation | Roca H, et al. (2008) Analysis of transcription factor interactions in osteoblasts using competitive chromatin immunoprecipitation. Nucleic Acids Res 36(5):1723-30 |
abstractText | Chromatin immunoprecipitation (ChIP) is a widely used technique for quantifying protein-DNA interactions in living cells. This method commonly uses fixed (crosslinked) chromatin that is fragmented by sonication (X-ChIP). We developed a simple new ChIP procedure for the immunoprecipitation of sonicated chromatin isolated from osteoblasts in the absence of crosslinking (N-ChIP). The use of noncrosslinked chromatin allowed development of a new modification of the ChIP assay: the combination of N-ChIP and competition with double-stranded oligonucleotides containing specific binding sites for individual transcription factors (Competitive N-ChIP). Using this approach, we were able to discriminate between individual binding sites for the Runx2 transcription factor in the osteocalcin and bone sialoprotein genes that cannot be resolved by traditional X-ChIP. N-ChIP assays were also able to detect several other types of chromatin interactions including those with Dlx homeodomain factors and nuclear proteins such as Sin3a that lack an intrinsic DNA-binding motif and, therefore, bind to chromatin via interactions with other proteins. |