Krayev A S, Kramerov D A, Skryabin K G, Ryskov A P, Bayev A A, Georgiev G P
Nucleic Acids Res. 1980 Mar 25;8(6):1201-15. doi: 10.1093/nar/8.6.1201.
Three copies of a highly repetitive DNA sequence B1 which is complementary to the most abundant class of mouse fold-back RNA have been cloned in pBR322 plasmid and sequenced by the method of Maxam and Gilbert. All the three have a length of about 130 base pairs and are very similar in their base sequence. The deviation from the average sequence is equal to 4% and the overall mismatch between each two is not higher than 8%. One of the recombinant clones used contained two copies of B1 oriented in the same direction. All of the B1 copies are flanked with sequences which possess nonidentical but very similar structure. They consist of a number of AmCn blocks (where m varies from 2 to 8 and n equals 1-2). These peculiar sequences in all cases are separated from B1 by non-homologous DNA stretches of 2-8 residues. In one case, a long polypurine stretch is located next to such a block. It consists of 74 residues most of which represent a reiteration of the basic sequence AAAAG. We have found two regions within the B1 sequence which are homologous to the intron-exon junctions, especially to those present in the large intron of the mouse beta-globin gene. It may indicate the involvement of the B1 sequence in pre-mRNA splicing.
一段与小鼠回折RNA中最丰富的一类互补的高度重复DNA序列B1的三个拷贝已被克隆到pBR322质粒中，并采用Maxam和Gilbert方法进行了测序。所有这三个拷贝的长度约为130个碱基对，碱基序列非常相似。与平均序列的偏差为4%，每两个之间的总体错配不高于8%。所使用的一个重组克隆包含两个同向排列的B1拷贝。所有B1拷贝的侧翼序列具有不同但非常相似的结构。它们由许多AmCn块组成（其中m从2到8不等，n等于1至2）。在所有情况下，这些特殊序列都通过2至8个残基的非同源DNA片段与B1隔开。在一种情况下，一个长的聚嘌呤片段位于这样一个块的旁边。它由74个残基组成，其中大部分是基本序列AAAAG的重复。我们在B1序列中发现了两个与内含子-外显子接头同源的区域，特别是与小鼠β-珠蛋白基因大内含子中的接头同源。这可能表明B1序列参与了前体mRNA的剪接。
