FIGURE 2 Gene-expression profiling using microarray analysis.
From the following article:
Technology Insight: tuning into the genetic orchestra using microarrays—limitations of DNA microarrays in clinical practice
Ambreen Abdullah-Sayani, Jolien M Bueno-de-Mesquita and Marc J van de Vijver
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Figure 2. Gene-expression profiling using microarray analysis.
The main steps involved and limitations of microarray analysis will be encountered. Two stages can be distinguished in microarray experiments: a pre-microarray experiment phase (tissue handling) and the microarray experiment phase (labeling of the RNA). In a microarray experiment the glass slide with the labeled DNA of interest plays a key role. As can be seen, a solid surface (in this example a glass microscope slide) contains thousands of spots. Each spot contains a large number of identical DNA fragments. Fluorescently labeled RNA from the samples are subsequently hybridized to the arrays. In this way, the amount of DNA fragments per spot indicates the expression level of a gene. The expression level of thousands of fluorescently labeled genes or spots on one microscope slide can be visualized with a fluorescent scanner. For each gene on the array, the amount of fluorescently labeled RNA bound represents the expression level of that gene in the tumor sample. The intensity of fluorescent signal can be measured and used in the statistical analysis. For each spot, the DNA fragments are derived from one specific gene. Figure courtesy of Dr R Kerkhoven. Abbreviations: DHFR, dihydrofolate reductase; E2F1, E2F transcription factor 1; RB, retinoblastoma; SRC, sarcoma.
