An origin of DNA replication and a transcription silencer require a common element.

A eukaryotic chromosomal origin of replication was identified in the yeast Saccharomyces cerevisiae. By several criteria, including map position, deletion analysis, and a synthetic form of saturation mutagenesis, the origin co-localized with the HMR-E silencer, which is a DNA element that represses transcription of the adjacent genes. A specific site within the silencer was required for both initiation of chromosomal replication and for repression of transcription. This analysis directly demonstrates that initiation of eukaryotic chromosomal replication is dependent on specific sequence elements and that a particular element can act in both initiation of chromosomal replication and regulation of transcription.