Mutational analysis of meiotic and mitotic centromere function in Saccharomyces cerevisiae.
Mutational analysis of meiotic and mitotic centromere function in Saccharomyces cerevisiae.
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DOI：
10.1093/genetics/117.2.203
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发表时间：
1987-10
期刊：
影响因子：
3.3
通讯作者：
Susan Cumberledge;J. Carbon
中科院分区：
文献类型：
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作者：
Susan Cumberledge;J. Carbon
酿酒酵母的着丝粒（CEN）由大约150 bp的DNA组成，包含3个保守序列元件：长度为78-86 bp的高A + T区（element II），左侧是保守的8-bp的element I序列（PuTCACPuTG），右侧是保守的25-bp的element III序列。我们对CEN3的I和II元件区域进行了结构-功能分析，构建了这些序列的突变，并随后确定了它们对有丝分裂和减数分裂染色体分离的影响。我们还研究了含有结构改变的CEN3序列的ARS质粒的有丝分裂和减数分裂分离行为。用长度相等的随机A + T序列代替元件II内A残基的周期束，使有丝分裂染色体不分离的频率仅增加4倍；然而，在保持长度的同时减少II元素的A + T含量会导致染色体不分离的频率增加40倍。元件II区的结构改变不减少总长度，对改变的染色体减数分裂分离行为的影响很小。含有元件I或元件II部分缺失的着丝粒保留了相当大的有丝分裂活性，然而携带相同突变的质粒在减数分裂I期间随机分离，表明这些序列对于在第一次减数分裂期间维持复制的姐妹染色单体的附着是必不可少的。完整的I元素序列与III元素区域之间的间隔对于着丝粒的减数分裂功能是绝对必要的。
A centromere (CEN) in Saccharomyces cerevisiae consists of approximately 150 bp of DNA and contains 3 conserved sequence elements: a high A + T region 78-86 bp in length (element II), flanked on the left by a conserved 8-bp element I sequence (PuTCACPuTG), and on the right by a conserved 25-bp element III sequence. We have carried out a structure-function analysis of the element I and II regions of CEN3 by constructing mutations in these sequences and subsequently determining their effect on mitotic and meiotic chromosome segregation. We have also examined the mitotic and meiotic segregation behavior of ARS plasmids containing the structurally altered CEN3 sequences. Replacing the periodic tracts of A residues within element II with random A + T sequences of equal length increases the frequency of mitotic chromosome nondisjunction only 4-fold; whereas, reducing the A + T content of element II while preserving the length results in a 40-fold increase in the frequence of chromosome nondisjunction. Structural alterations in the element II region that do not decrease the overall length have little effect on the meiotic segregation behavior of the altered chromosomes. Centromeres containing a deletion of element I or a portion of element II retain considerable mitotic activity, yet plasmids carrying these same mutations segregate randomly during meiosis I, indicating these sequences to be essential for maintaining attachment of the replicated sister chromatids during the first meiotic division. The presence of an intact element I sequence properly spaced from the element III region is absolutely essential for proper meiotic function of the centromere.