This web page was produced as an assignment for Genetics 564, an undergraduate course at UW‐Madison.
A DNA microarray, also known as DNA chip, is a collection of microscopic DNA clusters attached to a solid surface or 'chip'. Each DNA spot contains 10−12 moles of a specific short DNA sequence, known as probes. Probes are used to hybridize a target cDNA or mRNA sample. Probe-target hybridization is then visualized and quantified by detection of fluorophore-labeled targets to determine relative abundance of specific DNA sequences in the sample. [1]
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How does microarray illustrate gene expression?
Microarrays can be performed before and after exposing an organism to a specific stimulus or during a specific developmental stage, in order to determine the resultant gene expression. Gene expression level is proportional to the abundance of a specific sequence represented by intensity and color of the fluorescence. [2]
Microarray and MAOA
NCBI GEO database is an international online database that stores microarray data and other forms of functional genomics data submitted by researchers.[3] I managed to find only one study of MAOA using microarray via GEO, titled "Clorgyline treatment of VCaP cells". The researchers stated that high expression of MAOA has been identified in normal basal prostate epithelium and in high grade primary prostate cancer (PCa). Reversible Inhibition of MAOA with clorgyline was found to inhibit several oncogenic pathways in PCa cells, suggesting a clinical value of MAOA inhibitors as a pro-differentiation and anti-oncogenic therapy for high risk PCa. The researchers extended their studies by evaluating the growth of VCaP cells in the presence or absence of clorgyline and visualizing the MAOA gene expression changes in response to clorgyline by microarray. Results showed that treatment with clorgyline in vitro inhibited growth and altered the transcriptional pattern of VCaP cells in a manner consistent with the pro-differentiation and anti-oncogenic effects seen in treated primary PCa cells. These findings suggest that anti-depressant drugs that downregulate MAOA might be potential drugs to treat PCa.[4] Information from this study however, is less useful for the suppression of aggression, since what needed to be done is to upregulate MAOA in MAOA-deficient individuals.
Similar to RNAi and chemical genetics, the lack of microarray data on MAOA was as expected as the research on MAOA only started flourishing recently. Hopefully more information on MAOA will be available in the coming few years as more attention is given to the genetic factors of criminal aggression.
Similar to RNAi and chemical genetics, the lack of microarray data on MAOA was as expected as the research on MAOA only started flourishing recently. Hopefully more information on MAOA will be available in the coming few years as more attention is given to the genetic factors of criminal aggression.
Reference:
- What is a microarray? Coriell Institute for Medical Research. Retrieved April 18, 2014.
- Microarray technology. Premier Biosoft. Retrieved April 18, 2014.
- GEO Overview. Gene Expression Omnibus. Retrieved April 18, 2014.
- Flamand V, Zhao H, Peehl DM. (2010). Targeting monoamine oxidase A in advanced prostate cancer. J Cancer Res Clin Oncol 136(11):1761-71.