Gene expression microarrays estimation

How do we then envision the protein microarray as a proteomics tool We now estimate the human genome to comprise around 30,000 genes. For gene expression analysis using DNA microarrays, 1000 to 10,000 gene elements are often used. Since proteins undergo posttranslational modification (>200 different types see McDonald and Yates, 2000, Reference 40) and can occur as isoforms and multiprotein complexes, the number of protein expression elements needs to be much larger. 

The analysis of gene expression in one-channel microarray is quite different than in the two-channel case. This is mainly due to expression estimates that... 

For example, Imoto et al. (2003) introduced a statistical method for estimating a gene network based on both microarray gene expression data and various biological knowledge databases such as protein-protein and protein-DNA interaction. 

Photometer, Figure 2 DNA microarrays. The probes are complementary fragment oligonucleotides, of target DNA or mRNA are spotted onto the microarray surface. This type of array is typically hybridized with target cDNAs that are labeled with fluorophores. The samples are amplified by PCR and hybridized to the microarray, and then scanned in a microarray scanner to visualize fluorescence of the fluorophores on the chip. Absolute levels of gene expression cannot be determined, but relative differences in expression among different spots can be estimated when we used the two-color array, each color represents two different samples... 

Kim, H., Golub, G.H. and Park H., 2005, Missing Value Estimation for DNA microarray gene expression data local least squares imputation. Bioinformatics, 21(2) 187-98. 

Estimation of results is done by measuring the intensity of fluorescence, which corresponds to the amount of gene expressed in the sample (Pandey et al. 2003 Labana et al. 2005). The three major steps of a microarray technology are preparation of microarray, preparation of labeled probes, and hybridization and finally, scanning, imaging, and data analysis (Labana et al. 2005 Esteve-Nunez et al. 2001). 

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