Gene of resistance

A gene of resistance is a portion of DNA coding a substance allowing the survival of an organization in a medium comprising a toxic molecule or in a hostile environment.

In human health

A Gène of resistance indicates in a general way a gene which makes it possible to survive vis-a-vis a given condition. One can quote for example gene of the Hémoglobine transferred such as it is met in the Drépanocytose, or Anémie faliciforme, or in the Thalassémie S, which confers a certain resistance to the Malaria. In this case, the gene of resistance is a natural protein, the hemoglobin, which underwent a Mutation (responsible for a disease, in fact an anemia), but which confers a resistance vis-a-vis another disease, more mortal, the malaria. It is observed a larger incidence people having thalassaemias in the countries where the malaria is endemic.

All the genes of resistance are of course not responsible for diseases. One can quote the case of the Immune system, and genes of production of antibody by V-j recombination. However, the use of the gene term of resistance is not employed in this case, although he answers definition given perfectly Ci above.

In microbiology

The Penicillin, or very other Antibiotic having a core lactam, prevents the multiplication Bactérie S while interfering with the synthesis of the Peptidoglycane, an essential component of the external membrane of the positive bacteria Gram. In this example, the toxic molecule is penicillin. A possibility of exhaust developed by the bacteria is the synthesis of a protein which will degrade penicillin. This protein is called the β-lactamase. Degraded penicillin, the bacterium can develop. The Gène which codes protein of resistance is called gene of resistance.

transmission of gene of resistance

In a general way, the bacterial genes of resistance are not coded by the genome of the bacterium, but by a portion of extra DNA genomic: the Plasmide. This plasmide can be transmitted of one bacterium to the other by the phenomenon of bacterial Conjugaison. It is about a primitive form of exchange of genetic material. In this type of exchange, there exists a donneuse bacterium and a bacterium acceptrice. One speaks sometimes about the sex of the bacterium in this case. The phenomenon of conjugation has a considerable clinical importance in the appearance of multi-resistant germs. A multi-resistant organization has several genes of resistance to antibiotics

Use in research

In several scenarios of biological Research, it east can be interesting to allow to survival only certain organizations. The addition in the culture medium of a toxic agent, an antibiotic for example, makes it possible to kill all the organization not having gene of resistance. The gene of resistance can be introduced into a Plasmide coding a protein which one seeks to express. The plasmide thus contains: a gene coding protein of interest as well as a gene of resistance to an antibiotic. After a stage of transformation of the qualified bacteria, i.e. àprès the introduction into the cytoplasm of the cell of the plasmide, one makes grow the bacteria in a medium containing an antibiotic. Only the bacteria which will have integrated the plasmide will have gene of resistance and will be able to push. As on same the plasmide the protein of interest is coded, one is certain that the bacteria which will push also will contain this gene. The gene of resistance is used as tool allowing a Sélection (with the direction darwinien) of the bacteria of interest.

The term of " is often employed; protein produced by genetic Engineering " (for example the Insuline is produced in this manner). Behind this concept, the reality described in this article is hiding place.

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