大鼠高重复顺序DNA的核苷酸顺序分析及其与灵长类类α-DNA顺序的比较

The Nucleotide Sequence of Rat's Highly Repeated DNA and Comparison With the Alphoid DNA of Primate

啮齿目动物高重复顺序DNA的结构特征,虽已有人进行过分析,并提出大鼠DNA中有酶切位点分布独特的高重复顺序,也有人认为在Sprague-Dawlay大鼠中有类似于α-DNA大小的高重复顺序,并命名为α型(α-type),是否大鼠中也含有类α顺序,并没有人讨论过。我们对Wistar大鼠高重复顺序DNA进行了分离、纯化、分子克隆及核苷酸序列分析,测定了全序列为370bp,它也是具有酶切点分布独特的高重复顺序,但与前者存在着18％的差异性。我们对此顺序与灵长类类α-DNA进行了比较分析,发现二者在几方面都不存在相似之处,如此序列G-C含量占全部碱基组成的37.3％,而类α顺序的G-C含量约在40％以上,一些酶切位点也与类α-DNA完全不相同,另外在此序列的相应位置上也不具有灵长类类α-DNA的三个“冷点区”等等,由此得出大鼠这一高重复顺序并非类α顺序,而类α顺序只是灵长类动物所特有的。

In order to determine whether the Alphoid DNA sequence (termed α-type DNA) is contained in the Rat genome, A highly repeated sequence of Wistar Rat DNA has been studied by molecular cloning and DNA sequencing .This sequence con- sists of 370 base pairs, and shows a special distribution pattern of restriction sites, but'its nucleotide sequence has 18 percent difference as compared with the former result (1). Compared with the Alphoid DNA of Primate, this nucleotide sequence differences in several aspects are found. For instance, the G-C content is 37.3 percent of total base content in contrast to 40 percent or more in the Alphoid DNA, the restriction site distribution is also different from that of Alphoid DNA, and the three 'cold spots' (that attribute to the Alphoid DNA) are not found in the relevant locations. All these results seem to show that this highly repeated sequence in Rat genome is different from the Alphoid sequence and the Alphoid sequences may be the characteristic structural elements in Primate genome.