Ribosomal DNA insertion elements R1Bm and R2Bm can transpose in a sequence specific manner to locations outside the 28S genes.
Ribosomal DNA insertion elements R1Bm and R2Bm can transpose in a sequence specific manner to locations outside the 28S genes.
复制标题
核糖体DNA插入元件R1Bm和R2Bm可以以序列特异性方式转座至28S基因之外的位置。
DOI：
10.1093/nar/16.22.10561
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发表时间：
1988
影响因子：
14.9
通讯作者：
Eickbush,TH
中科院分区：
文献类型：
--
作者：
Xiong,Y;Burke,WD;Jakubczak,JL;Eickbush,TH
在某些昆虫中，核糖体28 S基因的一部分在特定位点被插入元件R1和R2中断（也称为I型和II型）。这些元件含有与逆转录酶同源的长开放阅读框。我们已经在家蚕中鉴定出这些插入核糖体DNA（rDNA）单位外位点的元件的拷贝。所有非rDNA元件的3′端与28 S基因内的元件相同;然而它们的5′端通常被截短。每个非rDNA拷贝都插入到与28 S基因中的靶位点相似的序列中。我们还通过基因组印迹分析证明了不同菌株的B。在rDNA单元外插入R1和R2的情况并不常见，而在rDNA基因座内发生了相当大的元件转换。一个B. Mori已经从其rDNA单位中丢失了R1的所有拷贝，而保留了正常水平的R2。在一个组织培养系中，R1和R2的水平都显著增加。这些发现为R1和R2是利用序列特异性内切酶整合到基因组中的逆转录转座因子的模型提供了相当大的支持。
A fraction of the ribosomal 28S genes in some insects are interrupted at specific sites by insertion elements R1 and R2 (also called Type I and II). These elements contain long open-reading frames with homology to reverse transcriptase. We have identified in the silkmoth,Bombyx mori, copies of these elements which have inserted into sites outside the ribosomal DNA (rDNA) units. The 3′ ends of all “non-rDNA” elements are identical to the elements within the 28S genes; however their 5′ ends are often truncated. Each non-rDNA copy has inserted into sequences that exhibit similarity to their target sites in the 28S gene. We also demonstrate by genomic blot analysis of different strains ofB. morithat insertions of R1 and R2 outside the rDNA units have been infrequent, while considerable turnover of elements has occurred within the rDNA locus. One race ofB. morihas lost all copies of R1 from its rDNA units, while retaining normal levels of R2. The level of both R1 and R2 have significantly increased in a tissue culture line. These findings add considerable support to the model that R1 and R2 are retrotransposable elements that utilize sequence specific endonucleases in their integration into the genome.