Chromatin Immunoprecipitation

Overview

Histones are proteins that help organize DNA in eukaryotic nuclei by serving as “scaffolds” around which DNA can be wrapped, forming a complex called “chromatin”. These proteins can be modified through the addition of chemical groups, and these changes affect gene expression. Researchers use a technique called chromatin immunoprecipitation (ChIP) to better understand which DNA regions associate with specific histone modifications or other gene regulatory proteins. Antibodies are used to isolate the protein of interest, and the bound DNA is extracted for analysis.

Here, JoVE presents the principles behind ChIP, discussing specific histone modifications and their relationship to gene expression and DNA organization. We then review how to perform a ChIP protocol, and explore the ways scientists are currently using this technique.

Procedure

Chromatin immunoprecipitation, or “ChIP,” is a technique used by researchers to assess protein-DNA interactions. Protein factors play important roles in the gene regulation; not only do they organize DNA in chromosomes, but they also bind to specific DNA sequences—called regulatory sites—to activate or repress expression. During ChIP, chromatin—which consists of DNA and its associated proteins—is “immunoprecipitated,” meaning that it is isolated through the use of antibodies.