5.1. Antibody Microarrays
Proteins can be separated and characterized via a number of different techniques (reviewed in [30]). One of these techniques is the use of antibody microarrays, which are similar to DNA microarrays, except that antibodies are printed on the chip instead of DNA probes [52]. Antibody microarrays were first used by Jamesdaniel et al. [53] to study hair cell damage in the inner ears of rats treated with cisplatin. This study identified the dynamic changes of 19 proteins that were either up- or downregulated and 15 of those were novel proteins that belong to either cell death or survival pathways [53]. Differential expression of proteins in the organ of Corti, lateral wall and modiolus of chinchilla showed enrichment of cell death pathways in both the sensory epithelia and modiolus [54]. Immunolabeling experiments confirmed the antibody microarray results by identifying the expression of E2F3 in nuclei and WSTF and FAK-p-Tyr577 in the stereocilia in the organ of Corti. Detection of FAK-p-Tyr577 supports the idea that post-translational modification of proteins can be identified using antibody microarrays, but cannot be detected using gene arrays [54]. It is necessary to have a large amount of tissue to study proteomics, and this problem was circumvented by an approach called “Subtractive Strategy Using Mouse Mutants” that can detect large number of proteins with only a small amount of starting material. Using the Pou4f3 mutant mouse model, the association of Pou4f3 in the inner ear with other genes, such as Notch1-4, gata3, p27Kip1, Eya1, S100a1, Tbx3, Shh, Fgfr3, Bmp5, Jag2 and Fkh10, were able to be identified [50].