YEAST CENTROMERE DNA IS IN A UNIQUE AND HIGHLY ORDERED STRUCTURE IN CHROMOSOMES AND SMALL CIRCULAR MINICHROMOSOMES
YEAST CENTROMERE DNA IS IN A UNIQUE AND HIGHLY ORDERED STRUCTURE IN CHROMOSOMES AND SMALL CIRCULAR MINICHROMOSOMES
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DOI：
10.1016/0092-8674(82)90147-7
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发表时间：
1982-01-01
期刊：
影响因子：
64.5
通讯作者：
CARBON, J
中科院分区：
文献类型：
--
作者：
BLOOM, KS;CARBON, J
用克隆的着丝粒DNA（CEN 3和CEN 11）作为标记探针，研究了酵母第III和XI号染色体着丝粒区的染色质结构。当用微球菌核酸酶消化来自分离的细胞核的染色质并将所得DNA片段电泳分离并印迹到硝酸纤维素滤膜上时，着丝粒核小体亚基被分解成比来自大部分染色质的亚基明显更明显的梯状结构。通过在着丝粒染色质内绘制精确的核酸酶切割位点，揭示了CEN序列的220-250 bp [碱基对]的离散保护区，其两侧是高度核酸酶敏感的位点。在该保护区的两侧，高度定相和特异性的核酸酶切割位点以核小体间隔（160 bp）存在，总长度为12-15个核小体亚基。两个着丝粒的染色质中的中央保护区跨越130 bp片段，该片段在功能性CEN 3和CEN 11 DNA之间表现出最高程度的序列同源性（71%）。这种独特的染色质结构保持在引入酵母的自主复制质粒上的CEN序列上，但不通过插入的酵母DNA侧翼的外源DNA序列繁殖。
The chromatin structure of the centromere regions of chromosomes III and XI in yeast was examined by using cloned functional centromere DNA (CEN3 and CEN11) as labeled probes. When chromatin from isolated nuclei is digested with micrococcal nuclease and the resulting DNA fragments separated electrophoretically and blotted to nitrocellulose filters, the centromeric nucleosomal subunits are resolved into significantly more distinct ladders than are those from the bulk of the chromatin. A discrete protected region of 220-250 bp [base pairs] of CEN sequence flanked by highly nuclease-sensitive sites was revealed by mapping the exact nuclease cleavage sites within the centrometric chromatin. On both sides of this protected region, highly phased and specific nuclease cutting sites exist at nucleosomal intervals (160 bp) for a total length of 12-15 nucleosomal subunits. The central protected region in the chromatin of both centromeres spans the 130 bp segment that exhibits the highest degree of sequence homology (71%) between functional CEN3 and CEN11 DNA. This unique chromatin structure is maintained on CEN sequences introduced into yeast on autonomously replication plasmids, but is not propagated through foreign DNA sequences flanking the inserted yeast DNA.