Gene Regulation: Expression and Definitions
In recent news, there has been a lot of conversation regarding DNA and RNA especially in relationship with the COVID-19 vaccine. What do all of these words mean? Why are they important to me?
Genes are the units of information passed to you from your parents that contain the information necessary for human growth and life. Mammalian genes code information in the form of DNA or deoxyribonucleic acid, which are strands of different nucleotides that code for various elements necessary for your physical traits. Most of these DNA sequences contain codes for proteins. All of your cells contain a copy of all of your genes within the nucleus of the cell, and depending on the location and function of the cell in your body, specific genes are used or expressed so that the cell can carry out a specific function. For example, a cell in your lung may have a specific role in transporting oxygen and carbon dioxide in and out of the body, while a cell on your skin may have a specific sensory role in touching and interacting with the external environment. These cells both contain the exact same genes, but express different ones to serve their specific purpose.
What is Gene Expression?
Gene expression is a broad term for the process where information encoded in DNA becomes a specific function. This is most commonly in the form of a specific protein, which through a series of steps within a framework called the central dogma, is created from a unique sequence in your DNA. The central dogma outlines this process, as your body transcribes DNA to RNA and then translates RNA to protein.
Real World Example: Rhodopsin and Eye Cells
One example of how DNA leads to a function is the presence of the protein rhodopsin in specialized cells in your eye called rod cells. In your eye there are many cells that help with processing light so that you can see, and many are present in the retina, the structure inside of the eye that captures light and helps turn this information into images that you can see. Rod cells are part of the retina and express a protein called rhodopsin which is crucial in allowing us to see in dim light. Without gene expression, we would not have this function of our eye that is essential in everyday life.
Real World Example: Vaccines
Vaccines are useful because they use the cells protein building machinery to create spike proteins that resemble the COVID-19 virus. This allows the body to create antibodies against COVID-19, which are the cells that help us fight infection. Vaccines target the translational step of the central dogma and introduce RNA into the body that interact with protein creating structures within the cells. This is a safe and effective way to boost your immunity to a specific virus!
What is Gene Regulation and Expression?
Gene regulation is the process that controls and changes what genes are expressed, often in response to changes in the external environment or signals from other cells. Genes can be regulated by making it difficult to transcribe DNA (our first step in the central dogma) which decreases gene expression or altering the final protein product so that it only functions in a specific setting. Though this is a complex topic, the main idea is that there are many mechanisms available to a cell that allow it to modulate its function through regulation of gene expression in response to its current environment and needs.
Real World Example: the Liver
Our liver is one of our most powerful organs, as it functions to detoxify the body from harmful substances. The liver does this through many enzymes which are protein structures that in this context break down these substances so that they can be excreted as waste. For the liver to remain healthy, it cannot constantly produce all of the enzymes necessary for all of the various toxins that could enter the body. Therefore, gene regulation allows for specific enzymes to be produced in response to the presence of a toxin rather than the liver be over worked. This is also important in understanding specific liver diseases, as they can result from the liver being overused in response to repeated exposure to various toxins.
Gene regulation and expression is essential to our daily lives!!
Author: Sydni Britton