Chromosome-specific alpha satellite DNA: nucleotide sequence analysis of the 2.0 kilobasepair repeat from the human X chromosome.
Chromosome-specific alpha satellite DNA: nucleotide sequence analysis of the 2.0 kilobasepair repeat from the human X chromosome.
复制标题
染色体特异性 α 卫星 DNA：对人类 X 染色体 2.0 kilobasepair 重复序列进行核苷酸序列分析。
作者：
J. Waye;H. Willard
人类X染色体的中心点周围区域的特征是一个串联重复的2.0千碱基对（kb） DNA片段家族，最初是通过用限制性内切酶BamHI切割人类DNA而发现的。我们在这里报告了重复家族克隆成员的完整核苷酸序列，并确定该x连锁DNA家族完全由α卫星DNA组成。我们的数据表明，2.0 kb重复序列由12个α卫星单体组成，排列在不完美的直接重复序列中。每个α X单体的长度约为171个碱基对（bp），其序列与先前描述的灵长类α卫星dna相同60-75%。12个α X单体在序列上是65-85%相同的，它们被组织成两个相邻的，由五个单体组成的相关块，加上另外两个与五聚体块内的单体相关的单体。第二份独立拷贝2.0 kb BamHI片段的部分核苷酸序列表明，2.0 kb重复序列实际上是X上的扩增单位。通过对12个α X单体序列的比较，得出了人类X染色体上α卫星DNA的171 bp的一致序列。这些序列数据，结合人类DNA和X染色体DNA的过滤杂交实验结果，使用2.0 kb重复内的亚区作为探针，为人类染色体个体具有不同α卫星家族的假设提供了强有力的支持，这些α卫星家族由限制性内切酶周期性和染色体特异性一级序列定义。
The pericentromeric region of the human X chromosome is characterized by a tandemly repeated family of 2.0 kilobasepair (kb) DNA fragments, initially revealed by cleavage of human DNA with the restriction enzyme BamHI. We report here the complete nucleotide sequence of a cloned member of the repeat family and establish that this X-linked DNA family consists entirely of alpha satellite DNA. Our data indicate that the 2.0 kb repeat consists of twelve alpha satellite monomers arranged in imperfect, direct repeats. Each of the alpha X monomers is approximately 171 basepairs (bp) in length and is 60-75% identical in sequence to previously described primate alpha satellite DNAs. The twelve alpha X monomers are 65-85% identical in sequence to each other and are organized as two adjacent, related blocks of five monomers, plus an additional two monomers also related to monomers within the pentamer blocks. Partial nucleotide sequence of a second, independent copy of the 2.0 kb BamHI fragment established that the 2.0 kb repeat is, in fact, the unit of amplification on the X. Comparison of the sequences of the twelve alpha X monomers allowed derivation of a 171 bp consensus sequence for alpha satellite DNA on the human X chromosome. These sequence data, combined with the results of filter hybridization experiments of total human DNA and X chromosome DNA, using subregions within the 2.0 kb repeat as probes, provide strong support for the hypothesis that individual human chromosomes are characterized by different alpha satellite families, defined both by restriction enzyme periodicity and by chromosome-specific primary sequence.