Immunoprecipitation, CoIP, and ChIP-seq
Immunoprecipitation (IP) is one of the most widely used techniques to isolate proteins and other biomolecules from complex mixture. It takes advantage of the high specificity of immunoglobulin molecules, and their strong affinity for specific antigenic targets.
A dominant Technique of the Past, Present, and Future.
IP techniques are frequently used to isolate the primary target in complex with other macromolecules (Co-IP), protein-DNA complexes (ChIP), specifically modified modified genetic material (methylated DNA IP, meDIP), RNA (RNA IP, RIP) or protein complexes containing specific posttranslational protein modifications.
ChIP: Identify DNA-Protein Interaction
An extension of the CoIP, ChIP (and other derived methods) are now the most commonly used techniques to identify the DNA/protein interface on specific proteins. The ChIP method isolates a specific protein, as in a conventional IP. Pertinent gene sequences bound to these proteins may then be identified.
Advanced genetic and proteomic techniques have increasingly expanded the reach and scope of ChIP. Coupling the ChIP assay with micorarray technology (ChIP-chip) and next-generation sequencing (ChIP-seq) permits identification of genome wide protein binding sites, and has been instrumental in expanding our understanding of the structure and function of the human genome. Through advances in sequencing and data processing technology, it has become possible to characterize genome wide protein DNA interaction sites with a high degree of fidelity and resolution.
Regardless of the complexity of the eventual method, the IP assay is still a mainstay of proteomics research. As such, at the heart of the IP method is an immunoreagent (either an antibody, or a similar alternative reagent). IP derived methods are regarded as one of the more technically challenging and demanding applications in which antibodies must perform, requiring a high degree of target affinity and an ever greater level of specificity. These criteria can only be reliably met by antibodies and other reagents that have been specifically characterized for IP-based applications.
Antibodies-online offers tens of thousands of antibodies and antibody alternatives approved for, and characterized in IP, ChIP, ChIP-seq and similar methods. We invite you to browse all of our products approved for Immunoprecipitation (IP), ChIP and similar methods.
A typical ChIP-seq protocol:
- Genomic DNA is fragmented enzymatically or mechanically after bound proteins have been crosslinked.
- DNA fragments are then co-immunprecipitated together with fixed proteins.
- The crosslink is reversed and the DNA fragments are processed and ligated to sequencing primers specific for the utilized NGS platform.
- After being amplified and purified based on their size the DNA pieces are sequenced and the obtained sequencing reads are mapped to a reference genome in order to identify protein binding sites.