[ad_1]
Gene expression profiling measures the activity levels of thousands of genes simultaneously, providing insight into how cells function. DNA microarray technology is used to measure mRNA levels in a control and experimental setting, which can be used for pure research or medical purposes, such as identifying effective drug targets for breast cancer.
Gene expression profiling is a way to measure the activity levels of thousands of genes simultaneously. Identifying gene expression patterns in an organism is the next step after an organism’s genome has been sequenced. Gene expression profiling experiments are usually performed on the entire genome of an organism simultaneously. Measuring levels of gene expression in an organism provides insight into how the body’s cells function during the cell cycle or in response to specific stimuli.
An organism’s genes can be in one of two states: on or off. When a gene is activated, it is transcribed into messenger RNA, which provides the instructions for making the protein encoded by the gene. When genes are activated, they are said to be expressed. When a gene is turned off, it is not transcribed into mRNA and is not expressed.
The DNA of even a single-celled organism contains thousands of genes, but only a fraction of those genes are turned on at any one time. The gene expression pattern within a cell at a particular time is referred to as its gene profile. Looking at the types of genes turned on in a cell can provide vast amounts of meaningful information about cells and organisms.
In a gene expression profiling experiment, DNA microarray technology is used to obtain a measure of the relative activity of previously sequenced genes. These experiments typically involve measuring quantities of mRNA in a control setting and an experimental setting, to determine the effects of one or more variables on gene expression. The use of a control is important because it establishes baseline mRNA levels for normal cellular conditions.
Observing how mRNA levels change in response to stimuli shows how cellular protein needs change in response to new environmental conditions. This information is useful for pure research purposes, but may also be important in medicine. For example, if breast cancer cells are used in DNA microanalysis, a profile could show that a certain type of receptor is active in breast cancer cells that is normally inactive. If the receptor is shown to be specific for cancer, it could prove to be an effective drug target.
Indeed, gene expression profiling has been used as a prognostic measure for breast cancer. This is helpful because women at the same stage of the disease can respond very differently to treatment and have very different prognoses. Using DNA microanalysis to create gene expression profiles has shown in at least one study that a certain gene expression profile in breast cancer cells correlates with a poor prognosis. This application of gene expression profiling technology helps identify women who may benefit from more aggressive treatment.
[ad_2]