Gene Expression

Video Transcript

When a cell transcribes the DNA sequence for a gene into a single RNA molecule, this is the first step of gene expression. We’ll start with this foundation to better understand the science behind what cancer is, the forces that drive it, and how to detect new biomarkers and treat the cancers they cause. In this video, we will look closely at this concept and how it applies to modern oncology.

HOW IS GENE EXPRESSION MEASURED?

We can measure the expression of a gene by counting how many RNA molecules for that particular gene are present within a single cell. A gene that is highly expressed will have a large number of these transcripts and a gene with low expression will have fewer. Genes that are turned off, or not expressed at all, will have an undetectable amount of RNA transcripts that correspond to that specific gene. Gene expression is like a volume knob, by creating more RNA molecules the cell can create more of that protein. During this process, the RNA transcript gets processed or spliced and turned into a mature transcript, and there are some oncogenic implications…meaning that this even can contribute to the development of a tumor.

GENE EXPRESSION AND PROTEIN SYNTHESIS

At this stage, proteins are created. They are inherently more complicated molecules. Proteins are made of twenty different monomers called amino acids. It’s the organization of the amino acid chain that gives the protein its function. Amino acids are strung together using RNA as a guide to translate the code on the RNA molecule into one amino acid after another into a chain of amino acids.  The chain then folds into its final product, which is the final step in gene expression. Every protein on earth that is synthesized by a living organism is coded for in this way.

IMMUNOHISTOCHEMISTRY TECHNIQUES

Caris Life Sciences can measure proteins using a technique called immunohistochemistry, where stain is used to see the specific proteins in a cell. Using this technique, a protein’s presence or absence and how much of a protein is expressed in a cell can be measured. Understanding a patient’s protein expression allows Caris to recommend therapies best suited to fight that specific patient’s tumor.