DNA sequence divergence and functional conservation at the STB locus of yeast 2 microns circle variants.
2 microns DNA isolated from industrial Saccharomyces cerevisiae yeasts exhibited extensive restriction fragment length polymorphisms. At least five 2 microns species were identified from eleven [cir+] strains. Southern hybridization mapped restriction fragment length polymorphisms at STB, a cis-acting locus essential for plasmid partitioning. Some 2 microns variants (e.g., 4110-2 microns and 4108-2 microns) had an altered number of 125-bp consensus repeats at STB. However, the corresponding region of 7754-2 microns has only approximately 70% nucleotide sequence homology with the 125-bp STB consensus repeat. YRp plasmids containing 7754-2 microns STB behave as YEp plasmids in laboratory yeasts, thereby indicating STB sequence divergence coupled to conservation of function.
Wei
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Department of Biology, University of Saskatchewan, Saskatoon, Canada.
Pelcher
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D000483:Alleles; D001483:Base Sequence; D015139:Blotting, Southern; D016384:Consensus Sequence; D004271:DNA, Fungal / Q000235:genetics; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010957:Plasmids; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D004271:DNA, Fungal