gene amplification


Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.

Gene amplification

The process by which a cell specifically increases the copy number of a particular gene to a greater extent than it increases the copy number of genes composing the remainder of the genome (all the genes which make up the genetic machinery of an organism). It is therefore distinguished from duplication, which is a precise doubling of the genome preparatory to cell division, and endoreduplication, which leads to endopolyploidy.

Gene amplification results from the repeated replication of the deoxyribonucleic acid (DNA) in a limited portion of the genome, in the absence of or to a much greater extent than replication of DNA composing the remainder of the genome. Thus is formed a cell in which the genes composing a limited portion of the genome are present in relatively high copy number, while the genes composing the remainder of the genome are present in approximately normal copy number. See Deoxyribonucleic acid (DNA)

Since gene amplification increases the copy number of a specific region of the genome without altering the copy number of genes composing the remainder of the genome, it would appear to offer an alternative method for developmental control of gene expression. By increasing the number of copies of a particular gene, the number of gene copies available for transcription could thereby be increased.

In a number of instances of gene amplification, the amplification phenomenon appears to be developmentally regulated, and the amplified copies of the gene are subsequently lost from the cell. Studies on cells in culture have demonstrated “amplification” of genes involved in resistance to specific drugs. See Gene, Gene action

gene amplification

[′jēn ‚am·plə·fə‚kā·shən]
(cell and molecular biology)
Any process by which a deoxyribonucleic acid sequence is disproportionately duplicated in comparison with the parent genome.
(genetics)
Repeated replication in a single cell cycle of the deoxyribonucleic acid (DNA) in a limited portion of the genome, resulting in an increase in the number of copies of a particular gene or DNA segment.
References in periodicals archive ?
Table 28: German Recent Past, Current & Future Analysis for Gene Amplification Technologies by Segment - Polymerase Chain Reaction (PCR) and Other Gene Amplification Markets Independently Analyzed with Annual Sales Figures in US$ Million for Years 2000 through 2010 (includes corresponding Graph/Chart) III-25
12,16,22,23] HER-2/neu overexpression is controlled not only by the degree of gene amplification but also by the rate of gene transcription and protein degradation.
Current recommendations for the evaluation of HER2 overexpression include the use of immunohistochemical methods initially on resection or biopsy specimens with cases having equivocal results further analyzed for Her2/neu gene amplification by in situ hybridization.
The original assay methods for measuring Her-2 gene amplification depended on Southern and so-called "slot-blotting" methods, which were expensive, time-consuming, and required fresh or frozen tissues.
Gene amplification restriction analysis holds promise to identify several mycobacteria simultaneously.
Conclusion: Although it was reported that hTERC gene amplification may partially contribute to increased telomerase expression and activity in leukemic cells, it is not possible to make such a conclusion based on the results of the this study, as hTERC amplification was not observed in the study group.
Chain Reaction (PCR) and Other Gene Amplification Markets
Fluorescence in situ hybridization was performed as described previously[6] to determine CD1 gene amplification in the carcinosarcoma of the tongue.
Breast cancer is one of the most common types of cancer in women in the US, and the presence of HER2 gene amplification indicates whether a breast cancer patient is a candidate for Herceptin (trastuzumab) treatment.
The most common detection methods for HER-2/neu include measurement of protein overexpression by the immunohistochemical assay HERCEPTest (7) and the detection of gene amplification by fluorescence in situ hybridization (FISH) [3] techniques (8), both approved by the US Food and Drug Administration.