A B2-L1 composite between rat histone H2A and H3 genes.
A B2-L1 composite between rat histone H2A and H3 genes.
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大鼠组蛋白 H2A 和 H3 基因之间的 B2-L1 复合物。
DOI：
10.1007/bf00360570
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Chae,CB
中科院分区：
文献类型：
--
作者：
Choi,YC;Han,BD;Chae,CB
高等真核生物的基因组包含高度重复的 DNA 序列，包括分散在整个基因组中独特基因序列之间的长和短散布重复序列（分别为 LINE 和 SINE）（Singer 1982）。通过对许多重复序列的序列分析，有人提出，重复序列转座和扩增所涉及的机制之一是通过将RNA产物的逆转录物整合到基因组DNA中而进行分散(Rogers 1985)。表明“逆位假说”的重复序列的几个结构特征是（i）Alu和B2序列中存在RNA聚合酶III的内部分裂启动子（块A和B）以及LI中的RNA聚合酶II启动子，（ii）在各种组织中，特别是在胚胎和生殖系细胞中存在包含这些序列的转录物（Bachvarova 1988；Skowronski和Singer 1985），（iii）寡核苷酸（dA）的存在(iv) 整个重复序列侧翼的短同向重复序列，包括寡核苷酸 (dA) 尾部，这可能是通过插入重复元件时靶位点复制产生的。最近，我们从 Charon 4A 中建立的大鼠基因组 HaeIII 文库中分离出了一个 9.5 kb 插入片段中含有大鼠组蛋白体细胞 H2A (sH2A)、H2B 和 H3 基因的基因组克隆（Choi 和蔡 1993）。在这项研究中，我们报告了 sH2A 基因下游约 2 kb 的序列，其中包含 B2-L1 复合物和组蛋白 H3 基因。如图1所示，组蛋白H3基因位于sH2A基因下游1514个核苷酸处，且方向与sH2A基因相同。大鼠组蛋白H3基因与四个小鼠组蛋白H3基因的序列比较显示与小鼠H3的同源性最高。 1-221 基因（Taylor 等人，1986）。两个H3基因的编码区内有27个碱基差异，而且都是沉默变化。这
The genome of higher eukaryotes contains highly repeated DNA sequences including long and short interspersed repeated sequences (LINEs and SINEs, respectively) dispersed in between unique gene sequences throughout the genome (Singer 1982). From the sequence analyses of a number of repetitive sequences, it was suggested that one of the mechanisms involved in the transposition and amplification of repetitive sequences is the dispersal by the integration of reverse transcripts of RNA products into the genomic DNA (Rogers 1985). Several structural features of repetitive sequences suggesting the" retroposition hypothesis" are (i) the presence of the internal split promoter (blocks A and B) for RNA polymerase III in Alu and B2 sequences and the RNA polymerase II promoter in LI,(ii) the presence of transcripts containing these sequences in various tissues, especially in embryonic and germ-line cells (Bachvarova 1988; Skowronski and Singer 1985),(iii) the presence of oligo (dA) stretch at the 3'end, and (iv) the short direct repeats flanking the entire repetitive sequences including oligo (dA) tail, which might have been generated by the target site duplication upon the insertion of repetitive elements.Recently, we have isolated a genomic clone containing rat histone somatic H2A (sH2A), H2B, and H3 genes in a 9.5-kb insert from a rat genomic HaeIII library established in Charon 4A (Choi and Chae 1993). In this study, we report an approximately 2-kb sequence downstream of sH2A gene containing a B2-L1 composite and histone H3 gene. As shown in Fig. 1, histone H3 gene is located 1514 nucleotides downstream from, and in the same orientation as, sH2A gene. Sequence comparison of rat histone H3 gene with four mouse histone H3 genes revealed the highest homology with the mouse H3. 1-221 gene (Taylor et al. 1986). There are 27 base differences within the coding regions of the two H3 genes, and all of them are silent changes. The