HIGHLY REPEATED DNA-SEQUENCE LIMITED TO KNOB HETEROCHROMATIN IN MAIZE
HIGHLY REPEATED DNA-SEQUENCE LIMITED TO KNOB HETEROCHROMATIN IN MAIZE
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DOI：
10.1073/pnas.78.7.4490
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发表时间：
1981-01-01
期刊：
影响因子：
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通讯作者：
PRYOR, AJ
中科院分区：
文献类型：
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作者：
PEACOCK, WJ;DENNIS, ES;PRYOR, AJ
从玉米基因组中分离出一个高度重复的DNA序列，作为放线菌素D/CsCl梯度的卫星序列。通过使用不同异染色质含量的玉米砧木，确定了该序列是一类异染色质的主要组成部分：球形异染色质，它可以出现在染色体补体中的23个位置。在大肠杆菌pBR322质粒中克隆了185个碱基对的重复单元，并测定了其核苷酸序列。该DNA序列在球形异染色质中存在，而在着丝粒、核仁和B染色体异染色质中不存在，这与之前描述的玉米这类异染色质的细胞遗传学分化相似。由于球形异染色质具有独特的细胞学外观，并且在减数分裂中具有独特的新中心活性，因此它与特定重复DNA序列的关联可能反映了该序列在细胞周期中的功能作用。
A highly repeated DNA sequence was isolated from the maize genome as a satellite in actinomycin D/CsCl gradients. By using maize stocks differing in their heterochromatin content it was established that the sequence is a major constituent of 1 class of heterochromatin: knob heterochromatin, which can occur at 23 locations in the chromosome complement. The repeating unit, of 185 base pairs, was cloned in plasmid pBR322 [Escherichia coli] and its nucleotide sequence was determined. The presence of this DNA sequence in knob heterochromatin and its absence from centromeric, nucleolar and B chromosome heterochromatin parallels the cytogenetic differentiation previously described for these classes of heterochromatin in maize. Because knob heterochromatin has a distinctive cytological appearance and is unique in showing neocentric activity at meiosis, its association with a particular repeated DNA sequence may reflect a functional role for the sequence in the cell cycle.