Characterization of Arabidopsis thaliana telomeres isolated in yeast.
Characterization of Arabidopsis thaliana telomeres isolated in yeast.
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DOI：
10.1093/nar/20.15.4039
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发表时间：
1992-08
影响因子：
14.9
通讯作者：
Eric J. Richards;Steven chao;Aurawan Vongs;Jin Yang
中科院分区：
文献类型：
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作者：
Eric J. Richards;Steven chao;Aurawan Vongs;Jin Yang
为了进一步了解植物染色体末端的基因组组织，我们采用功能互补策略分离了酵母（Saccharomyces cerevisiae）中的拟南芥端粒。获得了8个携带拟南芥端粒序列的酵母片段。对YpAtT1和YpAtT7两个片段所携带的植物序列进行了详细的鉴定。通过证明YpAtT1和YpAtT7插入dna的相应基因组序列在核外溶酶切过程中被优先降解，证实了它们的端粒起源。分离到的端粒限制性内切片段含有拟南拟南植物端粒特征的富含g的重复序列，以及亚端粒相关序列（TASs）。DNA序列分析显示，在端粒重复序列末端的着丝粒近端边界存在变异的端粒重复序列。YpAtT7中富含g的端粒重复序列两侧的TAS与其他拟南拟南植物端粒中存在的重复元件相对应，而更多的近端序列是一个端粒所特有的。YpAtT1 TAS在克隆起源的拟南植物Landsberg菌株中是独一无二的；然而，在哥伦比亚菌株中，Landsberg TAS与第二个端粒的交叉杂交很弱。胞嘧啶甲基化敏感内切酶的限制性内切分析表明，这两个TASs在基因组中高度甲基化。
In an effort to learn more about the genomic organization of chromosomal termini in plants we employed a functional complementation strategy to isolate Arabidopsis thaliana telomeres in the yeast, Saccharomyces cerevisiae. Eight yeast episomes carrying A. thaliana telomeric sequences were obtained. The plant sequences carried on two episomes, YpAtT1 and YpAtT7, were characterized in detail. The telomeric origins of YpAtT1 and YpAtT7 insert DNAs were confirmed by demonstrating that corresponding genomic sequences are preferentially degraded during exonucleolytic digestion. The isolated telomeric restriction fragments contain G-rich repeat arrays characteristic of A. thaliana telomeres, as well as subterminal telomere-associated sequences (TASs). DNA sequence analysis revealed the presence of variant telomeric repeats at the centromere-proximal border of the terminal block of telomere repeats. The TAS flanking the telomeric G-rich repeat in YpAtT7 corresponds to a repetitive element present at other A. thaliana telomeres, while more proximal sequences are unique to one telomere. The YpAtT1 TAS is unique in the Landsberg strain of A. thaliana from which the clone originated; however, the Landsberg TAS cross-hybridizes weakly to a second telomere in the strain Columbia. Restriction analysis with cytosine methylation-sensitive endonucleases indicated that both TASs are highly methylated in the genome.