Can "Jumping Genes" Make a Giant Leap for Gene Therapy?
Source: Philippa Phiache, Pharmaceutical Visions, Summer, 2002:3-23.
Transposons are genes that "leap" randomly from a location on a gene to another location on a chromosome. It is found that some transposons are linked to antibiotic resistance in bacteria and plants. There are many species in which transpons exist. Some of which are fish, fruit flies, and humans. It was thought that you couldn’t take a transposon from one species to give to another. New break through in genetics shown first in the resistance given to mosquitos for malaria.
Using a cut and paste enzyme called transposase to "leap" out of chromosomes, the transposon can transfer itself to another part of the cell’s genome. Without transposase the transposon is unable to move from place to place and one specie’s transposase will not work on another species transposons and visa versa. Now it is found that the transfer of this is possible.
The P-element in fruit flies can be transferred. After using a complicated and detailed scientific process to do this the transposon inserted can remain stable in another species. This allows us to create as many transgenic animals as needed. These allow the animal to be a sort of factory for the production of therapeutic proteins. Used in gene therapy to help kill cancer and can be used to treat sickle-cell anemia, muscular dystrophy, and cystic fibrosis.
Transposons were first discovered by the study of Indian corn. You see in Indian corn each different kernel can be a different color ranging from browns to purples to blues to yellows. The coloration of the kernels was found to be random and had no real connection with the genes of the parent corn plants and did not resemble it’s other generation mates in any rational way. So a scientist hypothesized that the corn had genes that made the kernel coloration completely random and that the genes were able to move from one spot on the chromosome to another. Also in doing so this would continue to make the kernels random colors. It turns out that scientist was right!!
Using this can allow a scientist to rearrange the DNA of the subject. Personally I do not think genes should be tampered with, but for the purpose of this it can be helpful. This can be used to have animals make certain proteins and substances that we can use in medicine or other fields that deal with chemicals. We could even, given time and more research help fix a person’s DNA that is either mixed up or broken.
For example, Billy has a defect that makes his hands have no sense of feeling due to the nerves in his hands having a defect in their transmitting mechanism. The instructions for making the mechanism in the nerve cells is controlled by a section of DNA at the beginning of a strand between two structural data sections. The thing is that this is caused by a substitution in that strand. So the scientists could go in with an animal’s DNA that cuts this part out and trades it with a section which would be correct (this section lies in the structural DNA which for all intents and purposes has no real purpose). Let’s just say this enzyme comes from a horse and it did control the receptors in the back of the horses eyes that lead to it’s brain. The transposase in the horse is altered slightly so that it will be stable in Billy’s body and a portion of it is injected into some of the nerve cells of Billy’s hands. After the scientist’s shock Billy’s nerve cells to make them active or attempt to be active because they are not connected properly. They then use a chemical to destroy the existing faulty connectors and stimulate the nerve cells to start to build new ones. So when the mRNA copies the new not faulty DNA and transfers it to the rest of the protein making system it will make a correct and working connecting site so for the first time ever Billy will be able to feel with his hands.
In cases like Billy’s and other people could be healed by this process if it can be brought to use. The only thing that is holding this type of healing back is the fact that there are some things dealing with genes and DNA that we just don’t understand yet.
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