To cross-link or not to cross-link?
The aim of cross-linking is to fix the antigen of interest to its chromatin binding site. Histones themselves generally do not need to be cross-linked, as they are already tightly associated with the DNA.Other DNA binding proteins that have a weaker affinity for DNA or histones may need to be cross-linked. This holds them in place and avoids protein dissociating from the chromatin binding site. Tip: The further away from the DNA your interaction of interest lies then the less effective ChIP will be without cross-linking. E.g. ChIP for histone modifications is unlikely to require cross-linking whereas non-histone proteins such as transcription factors and proteins contained in DNA binding complexes will probably need cross-linking.
The aim of cross-linking is to fix the antigen of interest to its chromatin binding site. Histones themselves generally do not need to be cross-linked, as they are already tightly associated with the DNA. Other DNA binding proteins that have a weaker affinity for DNA or histones may need to be cross-linked. This holds them in place and avoids protein dissociating from the chromatin binding site. Tip: The further away from the DNA your interaction of interest lies then the less effective ChIP will be without cross-linking. E.g. ChIP for histone modifications is unlikely to require cross-linking whereas non-histone proteins such as transcription factors and proteins contained in DNA binding complexes will probably need cross-linking.
