Murray A W, Szostak J W
Mol Cell Biol. 1986 Sep;6(9):3166-72. doi: 10.1128/mcb.6.9.3166-3172.1986.
We developed techniques that allow us to construct novel variants of Saccharomyces cerevisiae chromosomes. These modified chromosomes have precisely determined structures. A metacentric derivative of chromosome III which lacks the telomere-associated X and Y' elements, which are found at the telomeres of most yeast chromosomes, behaves normally in both mitosis and meiosis. We made a circularly permuted telocentric version of yeast chromosome III whose closest telomere was 33 kilobases from the centromere. This telocentric chromosome was lost at a frequency of 1.6 X 10(-5) per cell compared with a frequency of 4.0 X 10(-6) for the natural metacentric version of chromosome III. An extremely telocentric chromosome whose closet telomere was only 3.5 kilobases from the centromere was lost at a frequency of 6.0 X 10(-5). The mitotic stability of telocentric chromosomes shows that the very high frequency of nondisjunction observed for short linear artificial chromosomes is not due to inadequate centromere-telomere separation.
我们开发了一些技术，能够构建酿酒酵母染色体的新型变体。这些经过修饰的染色体具有精确确定的结构。第三条染色体的一个中着丝粒衍生物缺乏端粒相关的X和Y'元件（大多数酵母染色体的端粒处都有这些元件），它在有丝分裂和减数分裂中均表现正常。我们构建了酵母第三条染色体的一个环形排列的端着丝粒版本，其最接近的端粒距离着丝粒33千碱基。与天然中着丝粒版本的第三条染色体4.0×10⁻⁶的频率相比，这个端着丝粒染色体在每个细胞中的丢失频率为1.6×10⁻⁵。一个极其端着丝粒的染色体，其最接近的端粒距离着丝粒仅3.5千碱基，其丢失频率为6.0×10⁻⁵。端着丝粒染色体的有丝分裂稳定性表明，短线性人工染色体中观察到的极高不分离频率并非由于着丝粒-端粒分离不足所致。
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