All the biological information is stored in the DNA. When this information is metamorphosed, and used to make molecules or proteins, it is termed as gene expression. The whole process of converting the information to proteins is tightly regulated and is created by DNA transcription. This produces the Ribonucleic Acid, RNA. Later the RNA translates and creates protein.
All the life forms use the genetic information to create their subsequent generations. At various stages, the cell regulates the gene expression and that helps organisms to generate various cell types. It also helps the cells to adapt to the external and internal factors. The way the cells express the genes affects the traits of the organisms. Read on to understand more about it.
What is Gene expression Profiling?
Gene expression profiling is a technique that works on the theory that only a part of the genes gets encoded in the cell genome. That information is then transcribed into mRNA. The makeup of the protein is largely dependent on the mRNAs present in the cells.
The gene profiling indicates which genes are expressed and can measure a huge amount of genes simultaneously. There are many that can measure the entire genome of an organism all at once. It is to be noted that external and internal factors influence the gene expression including signals that it gets from other cells, cell division, cell functioning, etc. The profiling indicates the level of mRNA as well as the pattern expressed at the transcription phase. The profile that is created through the genome sequence indicates the cell functioning at that particular time.
There are various techniques through which the gene expression can be found and the most common among them is the DNA microarrays and the sequencing.
It is a technology that helps researchers analyze and investigate the gene expression in a single reaction effectively and quickly. It helps scientists to understand the fundamental aspects of growth and development and also explore the functional anomalies in the human body due to genes. In a typical microarray experiment, the mRNA is hybridized as per the original DNA template. Using many such DNA samples, an array is constructed. The level of mRNA that is attached to the array is a measure of the expression level of the genes. Since a number of mRNAs may be bound to the array all of that information is collected and a profile is created for the cells’ gene expression.
The other technology used for gene expression profiling is the sequencing with RNA. This type of sequencing has created a major impact on the transcriptome study. This technique helps to measure the expression across the mRNA of the organism. This sequencing helps to detect the gene fusions, nucleotide variants, detect changes that went undetected due to diseases, or in response to the treatments offered.
It is also used to categorize and predict diseases based on biomarkers. The major advantage of using transcriptome sequencing is that it can be used to discover expressed genes without knowing which gene it is.
Where is Gene expression profiling used?
It is used by molecular biologists, environmental toxicologists, and biomedical researchers. The profiling gives exact information on the Gene Expression and hence finds itself useful in many spheres. It is used to analyze cancer-related issues especially breast and gynecology, cardiovascular issues, auto-immune diseases in kids, molecular hematopathology, drug development for diseases and much more.
Reasons to use Gene Expression Profiling
This profiling acts as a diagnostic tool especially for people who are suffering from cancer. For example, certain genes may present themselves at higher levels in cancerous cells and these may, in turn, create a protein receptor. That receptor may be the cause of cancer and gene profiling as a diagnostic tool, this receptor can be targeted with the drug and treated. This profiling can be used to generate a hypothesis. Expression profiling can help in designing and testing experiments when there is little or no information is known regarding why a gene is expressed.
For example, it helps to determine if there is intercellular communication. If gene A expresses only when the cell is exposed to cell B, then tests can be made to learn if that is true. It can be used to determine the response of cells when exposed to drugs. It can be used to find the cellular response and find if the cell expresses genes to respond to toxic environments.
It is also used to learn about the effects of different stimuli on the gene expressions by changing the environment the cell is exposed to. It also helps to find the cell behavior, cellular function and if genes are active, dividing or other such useful information.
Gene Expression profiling is the best way to find the cell’s function
A lot of useful insights can be obtained about cell functioning and what genes the cell is expressing is known. It gives data on which genes are responsible for specific cellular behaviors. Having said that, the human body has about 20k protein-coding genes and not just one or two that produces millions of proteins. That is because of various reasons including splicing of the same genes producing different proteins. Also, alterations that it makes after proteins are created by the translation process.
All this means that more data is needed apart from the mRNA profile to determine the functioning of the cell or which cell produces which proteins. Despite the few drawbacks it has, gene profiling is still the best way to determine the functioning of the cells. This can be done without conducting too many experiments.
The data that is gathered from experiments conducted on the gene expression profiling needs to be analyzed properly as it is highly complex. When done properly, it gives useful insights into the expression of the genes in various conditions when exposed to different stimuli. That will further help in testing and redeveloping the theories. The data analysis may need to be done by various teams including the biostatisticians to get the right information.