Chromatrap, a more efficient, sensitive and robust method for ChIP
Epigenetics is the study of the molecular mechanisms which control gene expression in a potentially heritable way that do not involve changes in the underlying DNA sequence. Chromatin immunoprecipitation (ChIP) is a technique used to study the association of specific proteins, or their modified isoforms, with defined genomic regions.
ChiP is a fast growing research technique and is commonly used for mapping the DNA-protein interactions in cells which are crucial for correct gene regulation. For example, they may be used to determine whether proteins such as transcription factors and modified histones bind to a particular region of DNA of living cells or tissues.
In a ChIP assay, fragments of the DNA-protein complex (chromatins) are cross-linked in such a way so as to retain the specific DNA-protein interactions. The chromatin is then extracted and sheared either by sonication or enzymatic digestion into small fragments. The DNA/protein fragments are selectively immunoprecipitated using antibodies directed against the protein of interest and the resulting fractions treated to separate the DNA and protein components. Polymerase Chain Reaction (PCR), Real Time PCR, hybridization on microarrays, or direct sequencing are typically used to identify DNA fragments of defined sequence.
The new Chromatrap kits use revolutionary spin columns or microplates which contain discs of an inert, porous polymer to which protein A or G has been covalently attached. This patented format is unique. During an assay, the chromatin/antibody complex is selectively retained by the disc. Continue reading »