The site-specific ribosomal DNA insertion element R1Bm belongs to a class of non-long-terminal-repeat retrotransposons
The site-specific ribosomal DNA insertion element R1Bm belongs to a class of non-long-terminal-repeat retrotransposons
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位点特异性核糖体 DNA 插入元件 R1Bm 属于一类非长末端重复逆转录转座子
DOI：
10.1128/mcb.8.1.114-123.1988
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发表时间：
1988
影响因子：
5.3
通讯作者：
T. Eickbush
中科院分区：
文献类型：
--
作者：
Y. Xiong;T. Eickbush
两种类型的插入元件，R1和R2（以前称为I型和II型），已知中断几种昆虫物种的28 S核糖体基因。在家蚕中，每个元件占据了大约240个核糖体DNA单位的10%，而最多只有几个拷贝位于核糖体DNA单位之外。我们在这里展示了来自B的R1插入的完整核苷酸序列。桑（R1 Bm）。该5.1-内切酶元件包含两个重叠的开放阅读框（ORF），它们共同占据其长度的88%。ORF 1全长461个氨基酸，具有逆转录病毒gag基因的特征。ORF 2的长度为1，051个氨基酸，与逆转录酶样酶具有同源性。从核糖体位点的独立分离物的3'和5'末端的分析支持的建议，R1仍然是作为一个转座因子发挥作用。该元件在基因组中的精确位置意味着它的转座必须以显著的插入序列特异性发生。比较B的6个反转录转座子R1和R2的推导氨基酸序列。mori，黑腹果蝇的I因子和F元件，小家鼠的L1，和布氏锥虫的Ingi，揭示了在逆转录酶区域的相对高水平的序列同源性。像R1一样，这些元件缺乏长末端重复序列。因此，我们将这类相关元件命名为非长末端重复（non-LTR）反转录转座子。
Two types of insertion elements, R1 and R2 (previously called type I and type II), are known to interrupt the 28S ribosomal genes of several insect species. In the silkmoth, Bombyx mori, each element occupies approximately 10% of the estimated 240 ribosomal DNA units, while at most only a few copies are located outside the ribosomal DNA units. We present here the complete nucleotide sequence of an R1 insertion from B. mori (R1Bm). This 5.1-kilobase element contains two overlapping open reading frames (ORFs) which together occupy 88% of its length. ORF1 is 461 amino acids in length and exhibits characteristics of retroviral gag genes. ORF2 is 1,051 amino acids in length and contains homology to reverse transcriptase-like enzymes. The analysis of 3' and 5' ends of independent isolates from the ribosomal locus supports the suggestion that R1 is still functioning as a transposable element. The precise location of the element within the genome implies that its transposition must occur with remarkable insertion sequence specificity. Comparison of the deduced amino acid sequences from six retrotransposons, R1 and R2 of B. mori, I factor and F element of Drosophila melanogaster, L1 of Mus domesticus, and Ingi of Trypanosoma brucei, reveals a relatively high level of sequence homology in the reverse transcriptase region. Like R1, these elements lack long terminal repeats. We have therefore named this class of related elements the non-long-terminal-repeat (non-LTR) retrotransposons.
功能性祖先序列的确定和 A 型小鼠 L1 元件 5 端的定义。
影响因子：
5.6
作者：
Shehee,WR;Chao,SF;Loeb,DD;Comer,MB;Hutchison3rd,CA;Edgell,MH
通讯作者：
Edgell,MH
影响因子：
5.3
作者：
MARLOR, RL;PARKHURST, SM;CORCES, VG
通讯作者：
CORCES, VG