Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.

Gene amplification plays a pivotal role in malignant transformation of human cells. A plasmid with both a mammalian replication-initiation region (IR)/origin/replicator and a nuclear matrix-attachment region (MAR) is spontaneously amplified in transfected cells by a mechanism that involves amplifica...

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Main Authors: Naoya Okada, Noriaki Shimizu
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3790722?pdf=render
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author Naoya Okada
Noriaki Shimizu
author_facet Naoya Okada
Noriaki Shimizu
author_sort Naoya Okada
collection DOAJ
description Gene amplification plays a pivotal role in malignant transformation of human cells. A plasmid with both a mammalian replication-initiation region (IR)/origin/replicator and a nuclear matrix-attachment region (MAR) is spontaneously amplified in transfected cells by a mechanism that involves amplification at the extrachromosomal site, followed by amplification at the chromosomal arm, ultimately generating a long homogeneously staining region (HSR). Several observations suggest that replication initiation from IR sequences might mediate amplification. To test this idea, we previously dissected c-myc and DHFR IRs to identify the minimum sequence required to support amplification. In this study, we applied an improved analysis that discriminates between two amplification steps to the ß-globin RepP IR, which contains separate elements already known to be essential for initiation on the chromosome arm. The IR sequence was required at least for the extrachromosomal amplification step. In addition to the vector-encoded MAR, amplification also required an AT-rich region and a MAR-like element, consistent with the results regarding replicator activity on the chromosome. However, amplification did not require the AG-rich tract necessary for replicator activity, but instead required a novel sequence containing another AG-rich tract. The differential sequence requirement might be a consequence of extrachromosomal replication.
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spelling doaj.art-0e2db4014201497392880b20947397ca2022-12-21T19:25:33ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01810e7735010.1371/journal.pone.0077350Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.Naoya OkadaNoriaki ShimizuGene amplification plays a pivotal role in malignant transformation of human cells. A plasmid with both a mammalian replication-initiation region (IR)/origin/replicator and a nuclear matrix-attachment region (MAR) is spontaneously amplified in transfected cells by a mechanism that involves amplification at the extrachromosomal site, followed by amplification at the chromosomal arm, ultimately generating a long homogeneously staining region (HSR). Several observations suggest that replication initiation from IR sequences might mediate amplification. To test this idea, we previously dissected c-myc and DHFR IRs to identify the minimum sequence required to support amplification. In this study, we applied an improved analysis that discriminates between two amplification steps to the ß-globin RepP IR, which contains separate elements already known to be essential for initiation on the chromosome arm. The IR sequence was required at least for the extrachromosomal amplification step. In addition to the vector-encoded MAR, amplification also required an AT-rich region and a MAR-like element, consistent with the results regarding replicator activity on the chromosome. However, amplification did not require the AG-rich tract necessary for replicator activity, but instead required a novel sequence containing another AG-rich tract. The differential sequence requirement might be a consequence of extrachromosomal replication.http://europepmc.org/articles/PMC3790722?pdf=render
spellingShingle Naoya Okada
Noriaki Shimizu
Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.
PLoS ONE
title Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.
title_full Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.
title_fullStr Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.
title_full_unstemmed Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.
title_short Dissection of the beta-globin replication-initiation region reveals specific requirements for replicator elements during gene amplification.
title_sort dissection of the beta globin replication initiation region reveals specific requirements for replicator elements during gene amplification
url http://europepmc.org/articles/PMC3790722?pdf=render
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AT noriakishimizu dissectionofthebetaglobinreplicationinitiationregionrevealsspecificrequirementsforreplicatorelementsduringgeneamplification