Jumping genes help to make meningitis vaccine

Genes that hop from one part of a living thing's DNA to another are helping to create medication to protect against group B meningitis, a form of the disease for which no vaccine yet exists.

Discovered by scientists at Oxford University, the genes are being used by researchers at an Oxford hospital to identify the substances required in a vaccine to protect against group B meningitis.

Transposons, the scientific name for jumping genes, are stretches of DNA matter which appear to be useless, but highly successful, parasites. Clearly successful because nearly one third of human DNA is made up of transposons.

Being similar to other genes, the DNA of transposons is the code for making proteins. But the proteins made by transposons are enzymes whose only function is to cut the transposon out of its place on a chromosome and then insert it into another part of the same or another chromosome, apparently selected at random. Meanwhile, the transposon is recreated at its original site.

In this way transposons reproduce and spread within DNA. Transposons have been found in the DNA of every living organism studied to date. These useless, parasitic genes are very ancient and very successful. But now human scientists are putting these perfect parasites to work to benefit humanity.

When a transposon inserts itself at random into a new site on a chromosome, if its new home is in the middle of a functional gene, then that gene will be inactivated by the disruption caused by the transposon.

Therefore, if a transposon is inserted into a bacterium, and observed to insert itself into a particular gene, if the bacterium then becomes unable to infect its normal host, it can be safely concluded that the gene invaded by the transposon, or rather the protein it produces, is essential for the bacterium to be able to infect its host.

In this way transposons can be used to identify bacterial proteins which are good potential candidates for new vaccines, and good potential targets for new anti-bacterial drugs, since the bacteria cannot survive without them.

Treatment with a vaccine containing such proteins will hopefully stimulate the immune system to attack and destroy the proteins in any bacteria that enter the body, making it impossible for the bacteria to cause infection.

University of Oxford website