中国仓鼠卵巢细胞系CHOC 400中扩增的二氢叶酸还原酶基因的复制时间。

The replication timing of the amplified dihydrofolate reductase genes in the Chinese hamster ovary cell line CHOC 400.

作者信息

Caddle M S, Heintz N H

机构信息

University of Vermont, College of Medicine, Department of Pathology, Burlington 05401.

出版信息

Biochem Biophys Res Commun. 1990 Jul 16;170(1):134-9. doi: 10.1016/0006-291x(90)91250-v.

DOI:10.1016/0006-291x(90)91250-v

PMID:2372283

Abstract

We have examined the timing of replication of the amplified dihydrofolate reductase genes in the methotrexate-resistant Chinese hamster ovary cell line CHOC 400 using two synchronization procedures. DNA replicated in the presence of 5-bromodeoxyuridine was collected from cells of various times during the DNA synthesis phase and the extent of replication for defined sequences was determined by Southern blotting analysis of CsCl density gradient fractions. We report that under these conditions the DHFR gene replicates throughout the course of S phase in a mode similar to the bulk of the replicated genomic DNA. This contrasts with previous data that shows the non-amplified DHFR gene replicates during the first quarter of S phase. Therefore, we conclude that gene amplification alters the replication timing of the DHFR gene in CHOC 400 cells.

摘要

我们使用两种同步化程序，研究了甲氨蝶呤抗性中国仓鼠卵巢细胞系CHOC 400中扩增的二氢叶酸还原酶基因的复制时间。在DNA合成阶段的不同时间，从细胞中收集在5-溴脱氧尿苷存在下复制的DNA，并通过对CsCl密度梯度级分的Southern印迹分析来确定特定序列的复制程度。我们报告，在这些条件下，DHFR基因在S期全程以类似于大部分复制基因组DNA的模式进行复制。这与之前的数据形成对比，之前的数据显示未扩增的DHFR基因在S期的第一季度进行复制。因此，我们得出结论，基因扩增改变了CHOC 400细胞中DHFR基因的复制时间。