The chromosome end in yeast: its mosaic nature and influence on recombinational dynamics.
The chromosome end in yeast: its mosaic nature and influence on recombinational dynamics.
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发表时间：
1994-03
期刊：
影响因子：
3.3
通讯作者：
E. Louis;E. Naumova;Alice Lee;Gennadi Naumovt;James E. Habet
中科院分区：
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作者：
E. Louis;E. Naumova;Alice Lee;Gennadi Naumovt;James E. Habet
酵母染色体末端由几个不同的重复元件组成。在两株酿酒酵母染色体末端的6个克隆中，至少发现了7个不同的重复序列家族，其中包括先前鉴定的Y'和X元件。一些家族在不同的链球菌菌株之间拷贝数和位置上是高度可变的。酿酒酵母，而其他元素出现在拷贝数和位置恒定。三个重复序列元件是S.在其进化上的近亲奇异酵母中没有发现。另外两个重复序列在这两个S.酿酒酵母和S.矛盾的。这里所描述的这些都没有在下一个最接近的物种，贝酵母中发现（通过低严格性DNA杂交）。松散的X元素现在得到了更精确的定义。X是至少四个小（ca. 45-140 bp）的序列。还有一个潜在的“核心”X元件，约560 bp，可在所有末端发现。在X的远端，只有一个克隆在X和Y '的连接处具有（TG 1 -3）n端粒序列。这些内部（TG 1 -3）n序列的存在与单个Y'通过不等姐妹染色单体交换扩展成Y'串联阵列的能力相关。邻近X区域的共享重复元件的存在可以克服Y与相同大小类的其他Y异位重组的强烈偏好。酵母中的染色体末端在亚端粒重复结构和可变性方面是进化动态的。
Yeast chromosome ends are composed of several different repeated elements. Among six clones of chromosome ends from two strains of Saccharomyces cerevisiae, at least seven different repeated sequence families were found. These included the previously identified Y' and X elements. Some families are highly variable in copy number and location between strains of S. cerevisiae, while other elements appear constant in copy number and location. Three repeated sequence elements are specific to S. cerevisiae and are not found in its evolutionarily close relative, Saccharomyces paradoxus. Two other repeated sequences are found in both S. cerevisiae and S. paradoxus. None of those described here is found (by low stringency DNA hybridization) in the next closest species, Saccharomyces bayanus. The loosely characterized X element is now more precisely defined. X is a composite of at least four small (ca. 45-140 bp) sequences found at some, but not all, ends. There is also a potential "core" X element of approximately 560 bp which may be found at all ends. Distal to X, only one of six clones had (TG1-3)n telomere sequence at the junction between X and Y'. The presence of these internal (TG1-3)n sequences correlates with the ability of a single Y' to expand into a tandem array of Y's by unequal sister chromatid exchange. The presence of shared repeated elements proximal to the X region can override the strong preference of Y's to recombine ectopically with other Y's of the same size class. The chromosome ends in yeast are evolutionarily dynamic in terms of subtelomeric repeat structure and variability.