Whiteway M S, Ahmed A
Mol Cell Biol. 1984 Jan;4(1):195-8. doi: 10.1128/mcb.4.1.195-198.1984.
Wild-type strains of Saccharomyces cerevisiae exhibit mitotic recombination between the chimeric plasmid TLC-1 and the endogenous 2mu circle that involves sequence homologies between the two plasmids that are not acted on by the 2mu circle site-specific recombination system. This generalized recombination can be detected because it separates the LEU2 and CAN1 markers of TLC-1 from each other through the formation of a plasmid containing only the S. cerevisiae LEU2 region and the 2mu circle. This derivative plasmid is maintained more stably during vegetative growth than TLC-1, and strains which carry it frequently lose the endogenous 2mu circle. Therefore, TLC-1 can provide a convenient selection for [cir0] cells. Formation of this new plasmid is greatly reduced, but not eliminated, in strains containing the rad52-1 mutation. This indicates that generalized mitotic recombination between plasmid sequences utilizes functions required for chromosomal recombination in S. cerevisiae.
酿酒酵母的野生型菌株在嵌合质粒TLC - 1与内源性2μm环之间表现出有丝分裂重组，这涉及到两个质粒之间的序列同源性，而这些同源性不受2μm环位点特异性重组系统的作用。这种普遍重组可以被检测到，因为它通过形成一个仅包含酿酒酵母LEU2区域和2μm环的质粒，将TLC - 1的LEU2和CAN1标记彼此分开。这种衍生质粒在营养生长期间比TLC - 1更稳定地维持，携带它的菌株经常丢失内源性2μm环。因此，TLC - 1可以为[cir0]细胞提供一种方便的选择。在含有rad52 - 1突变的菌株中，这种新质粒的形成大大减少，但并未消除。这表明质粒序列之间的普遍有丝分裂重组利用了酿酒酵母染色体重组所需的功能。
