Repetitive sequence elements in an initiation locus of the amplified dihydrofolate reductase domain in CHO cells.

We have previously demonstrated that one of the replication initiation loci in the dihydrofolate reductase (DHFR) domain of Chinese hamster cells contains a repeated sequence that is enriched in the early-replicating fraction of the Chinese hamster genome. Here we present the sequence of the initiation locus, identify the relevant repeated element, and show that, while this element is enriched in early-replicating DNA, its synthesis is not confined to early S.