Wei X A, Pelcher L E, Rank G H
Department of Biology, University of Saskatchewan, Saskatoon, Canada.
J Bacteriol. 1991 Feb;173(3):1181-6. doi: 10.1128/jb.173.3.1181-1186.1991.
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.
从工业酿酒酵母中分离出的2微米DNA表现出广泛的限制性片段长度多态性。从11个[cir+]菌株中鉴定出至少5种2微米类型。Southern杂交将限制性片段长度多态性定位在STB，这是质粒分配所必需的顺式作用位点。一些2微米变体（例如，4110-2微米和4108-2微米）在STB处125 bp共有重复序列的数量发生了改变。然而，7754-2微米的相应区域与125 bp的STB共有重复序列只有约70%的核苷酸序列同源性。含有7754-2微米STB的YRp质粒在实验室酵母中表现为YEp质粒，从而表明STB序列发生了分歧但功能得以保留。
