Transposones' Action And Antibiotic Resistance: Gene Inactivation

Transposone is a DNA sequence which has transposition ability. It doesn’t need a homologues site in the target chromosome for the integration and have a cut and paste mechanism. It means tranposones move or jump one location to another location of a genome by themselves.

This can be resulted

• Changes in genome size
• Change the identity of the genome
• Resulting transposone mutagenesis
• Promote multiple antibiotic resistance
• Develop disease

Due to the addition of new DNA sequence the genome size is increased and the identity of the unique sequence is changed. Creating mutations in the genome Landing of new sequence inside to a gene promotes mutations of genes and it named as transposone mutagenesis. Due the landing of new sequence inside the gene, change the arrangement of nucleotide base parings and promote mutations. Some can be silent mutation. There is a mutation in the genome but it is not phenotypically expressed. Some time new phenotypic expressions are showed. For an example antibiotic resistance and diseases development. Some mutations can be lethal. Inactivation of gene expression Due to the integrations of new sequence the normal gene structure (arrangement of base paring) can be damaged and it lost its normal expressing ability. This also takes place due the transposone mutagenesis. This can be resulted due to the integrations of insertion elements (IS Element). It only contain IR sequence ( inverted repeat sequence) and Transposase gene which responsible for coding tranposase enzyme for the transposition. So,no new phenotypic expression and inactivate expression of the gene only. Develop disease If there is a genetic mutation is arising in a regulatory region of a gene, it leads to some diseases. For an example mutation in promoter regions promote over acting of genes and cause diseases.

• Inserting L1 inside the factor V111 gene responsible for hemophilia
• Inserting of L1 into APC gene responsible for colon cancer
• Duchene muscular dystrophy mutation in DMD gene

In the integrations of new sequence it cut the target genome at the site of target sequence, direct sequence repeats (DR sequence) after integration, this DR sequence duplicated. If the cutting sites not correctly repair it also allows dysfunction of cells. Multiple antibiotic resistances If the simplest type of transposones such as IS elements only have transposase gene, some has additional genes such as antibiotic resistance genes. Those types of tranposones named as composite transposones. Integration of those types of transposons leads multiple drug resistance. Many bacteria has ability to intergraded with more antibiotic resistance genes through the transposons and acquire multiple antibiotic resistant. For examples

• Acinetobacter calcoaceticus resistance to genatamicin, kanamicin, streptomycin
• Sterptococcus pneumonaiae resistance to kanamycin, tetracycline, Antibiotic resistance spread fastly through transposones and this is very common in hospital flora. Therefore this becomes a big problem in antibiotic medication. Therefore transposons leads mutations in the genome and these mutations can be
• Lethal mutations
• Silent mutations
• Inactivate mutations of normal gene expression
• Mutation with new gene expressions

And multiple antibiotic resistance activity. Not only the disadvantageous side of the transposones, there are some advantageous site of tranposone elements. This translocation helps to evaluation of organisms such as bacteria. In the same way some advantageous phenotypic characteristics are resulting. For a example Tol2 transposone is directly involve in pigmentation. This translocation advantageous to ornemantal fish production.