In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 72, No. 8_Supplement ( 2012-04-15), p. 2112-2112
Abstract:
The efficient and accurate repair of DNA double-strand breaks is critical for cell survival. HR provides an “error-free” way for the break repair. There is no loss of genetic information when homolog or sister chromatid are used for repair. They are mainly involved in HR and the frequency of non-sister chromatid interaction is greatly lower. However, when recombination occurs between non-sister chromatids, in the half of these cases it leads to loss of heterozygosity (LOH). This genetic alteration represents an important step in multistage carcinogenesis. Recently, the impact of LOH caused by HR in carcinogenesis of inherited cancer has been demonstrated to exceed impacts of point mutagenesis and non-homologous end joining. HR can be modulated by a variety of factors, and deep knowledge of the molecular background of this process is essential to predict and control corresponding genetic rearrangements. Some microsatellites represent “hot-spots” of recombination. In particular, one of the most abundant microsatellites, CA-repeats, enhances recombination between DNA molecules as observed in bacteria and eukaryotes. Previously we described spontaneous DNA-DNA interaction of homologous duplexes via HJ formation, and based on this investigation we elaborated the model system for HJs. We formed several types of HJs using: (1) random fragments restricted from pUC19; (2) fragments of the same sequence but amplified via PCR; (3) restricted fragments of the pE10 plasmid, harboring (CA/TG)31-repeat; (4) corresponding PCR products of the pE10 plasmid. Using different DNA polymerases we demonstrated that PCR amplification caused repetitive unit deletions/insertions in the (CA/TG)31-tract. It leaded to formation in PCR product of the fragment with (CA/TG)31-repeat of heteroduplexes and homoduplexes, differing mainly by one repetitive unit that is in accordance with previously published data. Corresponding restricted fragments with (CA/TG)31-repeats were significantly more stable. Using electron microscopy we showed that the majority of HJs formed by the PCR fragments with (CA/GT)31-repeats had their cross-points at the repetitive region, while the cross points of HJs formed by restricted fragments with (CA/TG)31-repeats and by entirely random sequences were mainly localized at the ends of the fragments. Demonstrated influence of (CA/TG)n-repeat instability on the branch migration is discussed in respect of the role of CA-microsatellites in homologous recombination. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2112. doi:1538-7445.AM2012-2112
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM2012-2112
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2012
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
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