Two modules from the hypersuppressive rho− mitochondrial DNA are required for plasmid replication in yeast

Abstract In the yeast hypersuppressive (HS) rho − mutants most of the mitochondrial genome is deleted, but the remainder containing one of the three rep sequences is amplified. One of these sequences, rep2 , and its flanking regions have been previously cloned and reported to promote autonomous plasmid replication in yeast. The present study suggests that the Ars activity associated with this HS rho − mitochondrial DNA (mtDNA) fragment is due to the presence in cis of at least two modules: (i) the 11-bp consensus sequence 5′- A T AAA C T ATAAA A T -3′, common to several ars sequences, and (ii) a palindromic sequence of the mitochondrial replicator. Proper spacing between the two modules, which varies from about 100 to 200 bp, is required for the Ars + activity.