Topic: About Gene Amplification
if you are interest ,below is part of the articles about Gene amplification.
1. Citation: Mukherjee K, Storici F (2012) A Mechanism of Gene Amplification Driven by Small DNA Fragments. PLoS Genet 8(12): e1003119. doi:10.1371/journal.pgen.1003119
DNA amplification is defined as a molecular process resulting in copy number increase of a discrete chromosomal DNA region. DNA amplification is found in many tumors, it is associated with several neuropathies and it can affect the susceptibility to certain diseases, such as systemic lupus erythematosus , . It is believed that DNA copy number increase is a major molecular mechanism driving oncogenesis in many kinds of cancer, and it affects tumor progression and clinical outcome . Gene amplification can in fact minimize the efficacy of drugs via overproduction of a protein that may be a drug target or via overproduction of a factor, which inactivates or eliminates the drug , . DNA amplification, together with DNA copy number reduction is a major source of genetic variation, which is not necessarily always pathogenic, but which can lead to polymorphisms between individual genomes in humans and other organisms –.....
2.Citation: Slack A, Thornton PC, Magner DB, Rosenberg SM, Hastings PJ (2006) On the Mechanism of Gene Amplification Induced under Stress in Escherichia coli. PLoS Genet 2(4): e48. doi:10.1371/journal.pgen.0020048
Gene amplification is the reiteration of a segment of a genome. It is a manifestation of genomic instability that is found in many tumors, notably some cases of neuroblastoma and some breast cancer in which it is associated with poor prognosis [1,2], and that arises during tumor progression in many others [1,2]. Amplification (and reduction) of genomic segments is now also appreciated to be among the most common of sequence variations, both pathogenic and polymorphic, between individual human genomes [3–5]. Amplification also occurs in microbes, in which it is implicated in the evolution of pathogenesis and antibiotic resistance ....
....DNA amplification can occur in response to stress. In Escherichia coli bacteria, starvation stress provokes amplifications that can allow E. coli ultimately to adjust to the starvation condition. This study elucidates several aspects of the mechanism underlying these stress-provoked amplifications. The data suggest a new model in which DNA replication stalls during starvation, and the end of the new DNA jumps to another stalled replication fork to create a duplicated DNA segment. The duplication can then amplify to many copies by genetic recombination. This model, if correct, can explain how stress provokes these genome rearrangements—by replication stalling. The general model may be useful for other long-distance genome rearrangements in many organisms. Stress can cause rapid and profound changes in the genome, some of which can give cells an advantage—this paper helps to explain how.----