How does gene therapy work?

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How does gene therapy work?
« on: 12/05/2009 09:30:01 »
Jim asked the Naked Scientists:
If a certain portion of a gene causes a certain disease, how do we use gene therapy to change that portion in millions, if not billions of cells to prevent the disease?

Jim of Mathews, Virginia USA

What do you think?


Offline Chelsie

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How does gene therapy work?
« Reply #1 on: 18/07/2009 19:01:34 »
Here is a simplified run down on how gene therapy works:

We use gene therapy to correct/treat genetic mutations that can alter the way in which a gene is expressed. Genes are transcribed into RNA which encodes for proteins. Therefore the gene sequence is directly related to the function of the protein (protein shape dictates function). Some mutations, small or large, can alter the folding of polypeptides into an incorrect shape, which can render a protein semi dysfunctional or completely dysfunctional. This is how genetic diseases arise.

We can correct this by inserting a normal gene into the genome of a human cell to replace the dysfunctional gene that is causing the disease. There are several ways to accomplish this but the most common way is to use a vector. A vector is a molecule that carries and transfers genetic material into a cell. For example, viruses can be used as vectors and are one of the most common vectors we use in gene therapy.

To understand why we can use a virus as a vector you must first understand how a virus works. If you are not already familiar, please view the following diagram to get a quick understanding of how viruses function:

As you can see from the image, the virus lands on a host cell and injects it's genetic material. The viral genetic material is then transcribed within in the cell to make more viruses. The host cell eventually bursts and the new viruses are released to repeat the process.

A viral vector uses the same process, however they do not carry viral genetic material and are genetically engineered to specifically carry and inject human genetic material into the human host cell. This means that the viral vector can carry the normal genetic material and inject it into a human cell with a mutated gene. The new and correct gene produces new and correct protein. With more newly functional protein being synthesized, the genetic disease will become less sever and can even be cured in some cases. The cells with the new and correct gene will then replicate, creating millions of cells that can synthesize functional protein.

It should be noted that we are still in the early stages of developing gene therapy and there is still more work to do before reaching full potential.

If you would like advanced information of gene therapy, recent molecular biology and molecular genetic text books usually have very good information. You can also visit which has decent information.

« Last Edit: 18/07/2009 20:03:17 by Chelsie »
If I were an enzyme I would be DNA helicase so I could unzip your genes.