一、技术简介

染色质免疫沉淀法（Chromatin immunoprecitation
，ChIP）是钻研体内DNA与蛋白质相互作用的沉要工具
。它能够活络地检测指标蛋白与特异DNA片段的结合情况
，还能够用来钻研组蛋白与基因表白的关系
。它能真实、齐全地反映结合在DNA序列上的调控蛋白
，是目前确定与特定蛋白结合的基因组区域或确定与特定基因组区域结合的蛋白质的最好步骤
。
根基道理是在活细胞状态下固定蛋白质－DNA复合物
，并将其随机堵截为肯定长度领域内的染色质幼片段
，而后通过免疫学步骤沉淀此复合体
，特异性地富集主张蛋白结合的DNA片段
，通过对主张片段的纯化与检测
，从而获得蛋白质与DNA相互作用的信息
。它能真实、齐全地反映结合在DNA序列上的调控蛋白
，是目前确定与特定蛋白结合的基因组区域或确定与特定基因组区域结合的蛋白质的一种很好的步骤
。
   

二、尝试步骤

1、 甲醛交联
2、 超声打碎DNA
3、 免疫沉淀
4、 消化蛋白质及解交联
5、 PCR扩增主张启动子片段
 

三、利用事俘

Fig1: ChIP analysis to detect in vivo binding of c-Jun to the dp5 promoter.
CGNs maintained in 25 or 5 K medium for 4 h were treated with formaldehyde to cross-link endogenous proteins and DNA. Samples of sonicated and purified chromatin were immunoprecipitated with a rabbit c-Jun antibody or a normal rabbit IgG. A, chromatins were sonicated into fragments about 0.5 kb in length. B, Western blotting analysis (WB) was performed using a monoclonal c-Jun antibody to demonstrate the immunoprecipitation (IP) specificity and efficiency and analyze c-Jun cellular protein levels. C, left, DNA isolated and purified from immunoprecipitated material was amplified by PCR with primers to amplify a 169-bp fragment of dp5 promoter spanning the ATF site (top), and a 173-bp fragment encompassing a canonical ATF sequence (TRE-jun2 site) located in the c-jun promoter was also amplified (bottom). The amplified PCR fragments were analyzed on 2% agarose gel.C, right, equal amounts of total genomic DNA (Input) were used for immunoprecipitation in each condition. Data are representative of three separate experiments.