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Antibody Microarrays an Introduction
Genomics and DNA microarray technology have allowed us to analyze almost all the mRNAs at one time and determine whether mRNA expression is changed in disease states. However, the concentration of a specific mRNA within a cell is usually poorly correlated with the actual abundance of the protein. mRNA half-lives in a cell may be hours long (even days), whereas protein levels can change quite quickly.
DNA microarrays leave much to be desired. They simply measure a STEP in the process leading to the final product, a fully functional protein (even proteins may need post-translational modifications and phosphorylation to function in a certain way!).
By measuring the amount of the specific protein directly, we can measure true expression of gene function.
When one takes into consideration the large number of post-translational modifications:
- Human cells may contain a million or more different protein variants due to the large numbers of post-translational modifications possible (for example phosphorylation on a different set of residues). In a given disease, one set of these modifications in one protein may be vital in the progression of the disease.
With the current state of antibody microarrays or antibody chips, science may now have solutions to this problem. An antibody microarray slide or “chip” could be spotted with thousands of known antibodies similar to the way a DNA microarray is made, and binding to antibodies on the chip could be measure when a biological sample is added. Protein chips are quickly becoming a fast and high-throughput method of profiling protein changes in disease and various cell conditions and stimuli.
Why spend 500$ on an antibody when you can have an entire antibody array of 500-2000 antibodies for about $2000?
Most Ab antibody microarray chips can be analyzed using standard DNA microarray fluorescent scanning equipment which is readily available in most hospitals and research institutes. The process is simple and the amount of data that is generated is quite large.
Process of using an Antibody Microarray:
- Extract total cellular proteins from biological samples of interest
- Label extracted proteins with fluorescent dyes (eg Cy-3 and Cy-5)
- Remove unbound dye (wash)
- Incubate labeled proteins with the antibody microarray
- Scan the array
- Analyze antibody microarray results
Ideas to think of:
- Companies will now prepare Custom Antibody and Protein Microarray Chips using peptide immunization or monoclonal antibodies.
- Differential protein expression analysis can be conducted using antibody microarrays allowing protein profiling.
Suppliers of Antibody Microarrays:
- Eurogentec – custom antibody microarrays and protein microarrays.
- Arrayit – Antibody Microarrays
- Sigma-Aldrich – Antibody Microarray kit. Microarray for signalling analysis: Panorama Ab Microarray Cell Signaling Kit