Biomedical Engineering Reference
In-Depth Information
RNA extraction
RNA
cDNA conversion
and labeling
cDNA
binding
glass slide microarray
laser and
imaging
gene expression
Fig. 1.5 Microarray process flow for measuring gene expression
1.2.3
Gene Expression Measurement
As described in the previous section, cell function and control results from the in-
teraction of genes and its products: RNA and proteins. All three components, DNA
(and genes), RNA, and proteins, are involved in gene expression regulation and have
high level of interaction. This interaction allows a significant amount of information
about the gene activity to be available in each of the components. In industry and
research, the focus is measurement at the RNA level, from which the gene expression
value can be inferred. In particular, high-throughput applications such as expression
microarrays have been recently developed which allow for measurement of tens of
thousands of RNA simultaneously.
The expression microarray system is comprised of both biochemical and opti-
cal imaging processes. A microarray is a slide plate with an array of thousands of
different probes attached to the surface in a grid pattern. Each probe is a single-
stranded DNA corresponding to a unique gene. The general steps (shown in Fig. 1.5 )
 
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