DNA sequence and functional analysis of an ARS-element from the zygomycete Absidia glauca.

A DNA fragment of mitochondrial origin from the mucoraceous fungus Absidia glauca promoting autonomous plasmid replication in Saccharomyces cerevisiae was sequenced and functionally characterised. We could show that the original mitochondrial insert cloned in Yip5 contains two regions with ARS activity which mutually inhibit each other. All plasmid derivatives replicating in yeast are rapidly lost during growth under non-selective conditions. In addition to one ARS consensus sequence with only one base substitution, the mitochondrial insert contains 18 related sequences with two base pair exchanges. With one exception all consensus sequences are preceded by sequence motifs strongly resembling ARS boxes.