Discrete functional elements required for initiation activity of the Chinese hamster dihydrofolate reductase origin beta at ectopic chromosomal sites

Steven J. Gray, Guoqi Liu, Amy L. Altman, Lawrence E. Small, Ellen Fanning

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

The Chinese hamster dihydrofolate reductase (DHFR) DNA replication initiation region, the 5.8 kb ori-beta, can function as a DNA replicator at random ectopic chromosomal sites in hamster cells. We report a detailed genetic analysis of the DiNucleotide Repeat (DNR) element, one of several sequence elements necessary for ectopic ori-beta activity. Deletions within ori-beta identified a 132 bp core region within the DNR element, consisting mainly of dinucleotide repeats, and a downstream region that are required for ori-beta initiation activity at non-specific ectopic sites in hamster cells. Replacement of the DNR element with Xenopus or mouse transcriptional elements from rDNA genes restored full levels of initiation activity, but replacement with a nucleosome positioning element or a viral intron sequence did not. The requirement for the DNR element and three other ori-beta sequence elements was conserved when ori-beta activity was tested at either random sites or at a single specific ectopic chromosomal site in human cells. These results confirm the importance of specific cis-acting elements in directing the initiation of DNA replication in mammalian cells, and provide new evidence that transcriptional elements can functionally substitute for one of these elements in ori-beta.

Original languageEnglish (US)
Pages (from-to)109-120
Number of pages12
JournalExperimental Cell Research
Volume313
Issue number1
DOIs
StatePublished - Jan 1 2007

Keywords

  • DHFR
  • DNA replication
  • Dinucleotide repeat
  • Ori-beta
  • Origin
  • Transcription factor

ASJC Scopus subject areas

  • Cell Biology

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