Mutations in ARS1 increase the rate of simple loss of plasmids in Saccharomyces cerevisiae

Autonomously replicating sequence (ARS) elements are DNA sequences that promote extrachromosomal maintenance of plasmids in yeast. Mutations generated in vitro in the ARS1 region were examined for their effect on plasmid maintenance in a yeast centromeric plasmid. Our data show that mutations in the regions surrounding the ARS1 consensus sequence cause increases in the frequency of simple loss (1:0) event without affecting the rate of non‐disjunction (2:0). Removal of the consensus itself causes a drastic increase in the rate of simple loss. Sequences sensitive to mutagenesis were identified in each flanking region and differ with respect o their location and importance o ARS function. These results suggest that the role ARS1 plays in plasmid maintenance deals with the replication and/or localization of the plasmid in yeast.