Course: SAT 170 Introductory Biotechnology

Unit 7 Learning Module

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Page 5 of 5
DNA Technology Part 2 (continued)

Gene Therapy

The technology of using a normal, healthy copy of a gene to replace a missing or non-functional gene is known as gene therapy. In theory, these normal, healthy genes will be incorporated as part of the individual’s genome allowing them to permanently cure a particular disease. The basic steps for gene therapy include the following: isolating a gene from a healthy individual, inserting that gene into a vector, and finally suing that vector to carry the gene into an individual with the disease. The introduction of such genes is typically done using a modified virus. This virus is introduced into the body cells of an individual with a particular genetic disorder, so that those body cells may receive a normal, or healthy, copy of that gene. This method is known as somatic gene therapy because it targets the somatic cells of an individual (all body cells other than the gametes). Germ-line gene therapy would target the gametes of an individual to ensure that the genetic disease would not be passed on. In this case, the normal, healthy gene is inserted in to the gamete (e.g. sperm or egg) so that when that gamete is involved in reproduction, the resulting offspring would carry the normal or healthy gene.

This image illustrates the use of a virus, such as a retrovirus, to introduce a healthy copy of a gene into an individual’s cells which carry a diseased version of that gene during gene therapy.
Protein Therapy

Protein therapy is similar to that of gene therapy, but rather than replacing a missing or non-functional gene, researchers are replacing a missing or non-functional protein. Unlike the DNA content of our cells which is relatively stable, the protein content is constantly fluctuating. Thus, treatment with protein therapy must be done repeatedly and often frequently to effectively manage a particular disease. Protein therapy is done following these basic steps:  isolating a gene from a healthy individual, inserting that gene into an organism (or host cell) which will express that gene, collecting and purifying the protein product, and finally inserting the protein product into an individual with the disease.

One of the first applications of protein therapy was the use of bacteria to produce insulin for the treatment of diabetes.