Sequence at insertion site of E.Tn retrotransposon into an immunoglobulin switch region suggests a role for switch recombinase.
Sequence at insertion site of E.Tn retrotransposon into an immunoglobulin switch region suggests a role for switch recombinase.
复制标题
E.Tn 逆转录转座子插入免疫球蛋白开关区域的插入位点的序列表明开关重组酶的作用。
DOI：
10.1093/nar/19.2.396
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发表时间：
1991
影响因子：
14.9
通讯作者：
Dunnick,WA
中科院分区：
文献类型：
--
作者：
Elenich,LA;Dunnick,WA
E. Tn（早期转座子样）元件是鼠逆转录转座子样元件家族（1）。这些5.6 kb的序列两侧是两个330 bp长的末端重复序列（LTR），在小鼠基因组中存在约1000个拷贝（2）。这些元件在早期胚胎发生和浆细胞瘤中被转录，但它们不包含重要的开放阅读框架，因此不能编码参与其转座的蛋白质。然而，E. Tn元件已被证明在四个病例中整合到不同的位点：三个在浆细胞瘤P3及其衍生物中（3-5），一个在T位点中（6）。浆细胞瘤P3 DNA中的Tn发生在免疫球蛋白转换（S）区。插入-yI开关区域似乎是通过正常的转座过程发生的：LTR是相同的，插入导致靶序列的六个碱基对的复制（4）。对插入到S ′ y2 a区的5 ′端进行了鉴定，发现E. Tn元件，包括5 'LTR。为了进一步理解这种缺失并鉴定S-y2 a靶序列，我们克隆了插入的3 '端。
E. Tn (for early transposon-like) elements are a family of murine retrotransposon-like elements (1). These 5.6 kb sequences are flanked by two 330 bp long terminal repeats (LTRs) and are present in approximately 1000 copies in the mouse genome (2). These elements are transcribed in early embryogenesis and in plasmacytomas, but they contain no significant open reading frames and are therefore unable to code for proteins involved in their transposition. Nevertheless, E. Tn elements have been shown to have integrated into different loci in four cases: three in the plasmacytoma P3 and its derivatives (3-5), and once into the T locus (6).Two of the insertions of E. Tn in plasmacytoma P3 DNA have occurred in immunoglobulin switch (S) regions. The insertion into the-yI switch region appears to have occurred via a normal transposition process: the LTRs are identical and the insertion resulted in the duplication of six base pairs of the target sequence (4). Characterizationof the 5'end of the insertion into an S'y2a region revealed a deletion of the first 631 bp of the E. Tn element, including the 5'LTR. In order to further understand this deletion and to identify the S-y2a target sequence, we cloned the 3'end of the insertion.