title: Identification of the origin of replication of the eukaryote Dictyostelium discoideum nuclear plasmid Ddp2.
abstract: Ddp2 is a 5.8-kb, high-copy-number, nuclear plasmid found in the eukaryote Dictyostelium discoideum. We have identified two functional domains, a large open reading frame (Rep gene) and a 626-bp fragment containing an origin of replication (ori). The ori, when cloned into a shuttle vector, confers stable extrachromosomal replication in D. discoideum, provided that the Rep gene, which acts in trans, is integrated into the host genome. Ddp2 carries a 501-bp imperfect inverted repeat, and part of the ori overlaps with one of these repeats. The ori sequence contains two direct repeats of 49 bp comprising two 10-bp "TGTCATGACA" palindromes separated by a poly(T.A) sequence. Deletion of either 49-bp repeat abolished extrachromosomal replication.
authors.affiliation: School of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.
authors.forename: A C
authors.initials: AC
authors.lastname: Chang
authors.forename: M B
authors.initials: MB
authors.lastname: Slade
authors.forename: K L
authors.initials: KL
authors.lastname: Williams
mesh_terms: D001483:Base Sequence; D002467:Cell Nucleus / Q000502:physiology*; D015825:Chromosomes, Fungal; D003001:Cloning, Molecular; D004261:DNA Replication; D004271:DNA, Fungal / Q000235:genetics / Q000302:isolation & purification; D004023:Dictyostelium / Q000235:genetics*; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D015183:Restriction Mapping; D014170:Transformation, Genetic
chemical_list: D004271:DNA, Fungal