The terminal DNA structure of mammalian chromosomes
The terminal DNA structure of mammalian chromosomes
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DOI：
10.1093/emboj/16.12.3705
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发表时间：
1997-06-16
期刊：
影响因子：
11.4
通讯作者：
Wellinger, RJ
中科院分区：
文献类型：
--
作者：
McElligott, R;Wellinger, RJ
在几乎所有真核生物中，端粒DNA由数量可变的短直接重复序列组成。虽然已经确定了许多物种的端粒重复序列的初级序列，但真正的后生动物染色体末端具有着丝粒的实际DNA结构尚不清楚。这表明，在哺乳动物的染色体末端发现了形成染色体3‘端的一条悬垂的富含G的链。此外，至少在一些端粒上，突出部分大于或等于45个碱基长。来自完全转化的组织培养细胞和正常G(0)滞留外周血白细胞的染色体上存在这种令人惊讶的长悬突。因此，无论细胞是活跃分裂还是停滞，都发现了非常相似的末端DNA排列。这些数据表明，哺乳动物和可能所有脊椎动物的染色体末端都由富含G的链组成，这些突出部分可能比之前预期的要大得多。
In virtually all eukaryotic organisms, telomeric DNA is composed of a variable number of short direct repeats. While the primary sequence of telomeric repeats has been determined for a great variety of species, the actual physical DNA structure at the ends of a bona fide metazoan chromosome with a centromere is unknown. It is shown here that an overhang of the strand forming the 3' ends of the chromosomes, the G-rich strand, is found at mammalian chromosome ends. Moreover, on at least some telomeres, the overhangs are greater than or equal to 45 bases long. Such surprisingly long overhangs were present on chromosomes derived from fully transformed tissue culture cells and normal G(0)-arrested peripheral leukocytes. Thus, irrespective of whether the cells were actively dividing or arrested, a very similar terminal DNA arrangement was found. These data suggest that the ends of mammalian and possibly all vertebrate chromosomes consist of an overhang of the G-rich strand and that these overhangs may be considerably larger than previously anticipated.