Avoiding non-specific DNA binding in ChIP assays - (Oct/19/2005 )
Hi again, I have another doubt related to CHiP assays. I have added BSA and sonicated DNA to the protein A Sepharose, but I keen op founding in controls taht DNA (in a strain without tagging) binds to the slurry...How can I block the resin?
You should also try blocking with sheered salmon sperm DNA (you can buy this cheap). In addition check your protocol for your wash conditions, it sounds like your washes may not be stringent enough to remove the non-specific binding going on.
I use sperm DNA + BSA for blocking, and I wash using Staph-A-Buffer + sodium deoxycholate.
Does anyone know how much salmon sperm to add to beads incubated with antibody?
In the past I have only blocked with BSA...