Amplification chromosomal

A diagnostic method using fluorescence labeled DNA probes to detect and quantify the number complementary chromosomal sequences on a cellular resolution. A related technique that also allows assessment of gene amplifications, but without precise quantification of copy numbers is the chromogenic in situ hybridization (CISH). Here, instead of a fluorescent dye an enzyme that can generate a colored precipitate in the tissue samples is coupled to the DNA probe. 

The linear RCA method can use both target and signal amplification. A DNA circle (such as a plasmid, circular vims or circular chromosome) is amplified by polymerase extension of a complementary primer. Up to 10 tandemly repeated, concantemerized copies of the DNA circle are generated by each primer, resulting in one single-stranded, concantemerized product. ... 

Roy, K., et al. Chromosomal localization of the murine RFC-1 gene encoding a folate transporter and its amplification in an antifolate resistant variant overproducing the transporter. Cancer Genet. Cytogenet. 1998, 305, 29-38. 

Ruano G, Kidd KK. Direct haplotyping of chromosomal segments from multiple heterozygotes via allele-specific PCR amplification. Nucleic Acids Res 1989 17[20] 8392. 

Kitayama Y, Igarashi H, Sugimura H. Amplification of FISH signals using intermittent microwave irradiation for analysis of chromosomal instability in gastric cancer. Mol. Pathol. 1999 52 357-359. 

A combination of pulse field gel electrophoresis to separate large DNA restriction fragments, amplification by PCR, and detection with p53 cDNA probes has been useful to study chromosomal deletions and p53 mutations in colorectal cancers (Bl). 

Boschman, G. A., Buys, C. H., van der Veen, A. Y Rens, W., Osinga, J., Slater, R. M and Aten, J. A. (1993) Identification of a tumor marker chromosome by flow sorting, DNA amplification in vitro, and in situ hybridization of the amplified product. Genes Chromosom. Cancer 6, 10-16. 

To further confirm the data, we performed Y chromosome PCR. The sensitivity of this method was 10 or 1000 cells detected in a total of 10 cells that were screened. Organs of female rats infused with male MSC were harvested at 24 hand at day 3 after infusion. Real-time quantitative PCR withY chromosome-specific primers showed amplification only in the lungs at 24 h after cell infusion (Figure 5), whereas kidney, liver, spleen, and bone marrow were negative, thereby further corroborating our results about a clearance of MSC from kidneys long-term. 

As in cancer predisposing syndromes, these genetic alterations are sometimes carried in the germline. Among human tumours, heritable mutations are an exception. Most alterations are acquired in somatic life in the form of chromosomal translocations, deletions, inversions, amplifications or point mutations. Certain oncogenic viruses play important roles in a few human tumours. Examples are human papilloma-virus in cervical cancer and skin tumours, Ep-stein-Barr virus in nasopharyngeal carcinoma and Burkitt s lymphoma, and human T-cell leukaemia viruses (e.g. HTLV-I, HTLV-II) in T-cell leukaemia. 

Amplification The production of additional copies of a chromosomal DNA sequence, found as either intrachromosomal or extrachromosomal DNA. [nih]... 

During the amplification cycles of the PCR, the Taq DNA polymerase copies the DNA between the primers. Because numerous areas throughout the bacterial chromosome are amplified, many potential genetic differences can be detected. Figure D.4 shows a chip analysis of two samples of bacterial DNA amplified by rep-PCR. The gel electrophoresis results clearly show that the bacteria samples are different strains, as there are band differences appearing at approximately... 

Radiation can also cause larger-scale errors involving many nucleotides. In some cases, the change in the chromosome is visible with a microscope (called chromosome aberrations). Some important types of chromosome aberrations are deletions, amplification, and translocation. Deletions are simply loss of a segment of DNA with the consequence... 

Caron H, Peter M, van Sluis P et al. Evidenee for two tumor suppressor loci on chromosomal bands lp35-36 involved in neuroblastoma one probably imprinted, another associated with A-myc amplification. HumMolec Genet 1995 4 535-539. 

In an analysis of 2210 solid tumors (27 different tumor types) every chromosome region demonstrated some level of both loss and amplification (20). However, loss and amplification of the same chromosome region were rarely seen in the same tumor type, and some chromosome regions were tumor specific for example, the short arm of chromosome 12 (12p) is amplified in 96.3% of testicular cancers and 0% of renal cancers (20). 

The clinical implications of both amplification and loss in tumors have been studied. In a study of 29 Dukes C colorectal cancer patients, those with tumors that had two or more chromosomal regions of gain or loss had significantly better prognosis than patients with less (p = 0.02) (21). Loss of chromosome 5q and lack of 8q amplification in serous ovarian cancer n = 96) is associated with improved prognosis (5-year survival of 75% versus 0% with no loss on 5q and amplification on 8q p = 0.0007) (22). In childhood ALL the amplification of specific chromosomes, chromosome regions, and genes has been associated with chemotherapy resistance and clinical outcome (23,24). 

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