Sentry J W, Smyth D R
Department of Genetics, Monash University, Clayton, Vic., Australia.
Mol Gen Genet. 1989 Jan;215(2):349-54. doi: 10.1007/BF00339741.
A 9.35 kbp element with long terminal direct repeats (LTRs) of 2.4 kbp has been characterized from the large genome of Lilium henryi. The organization of the element, named del, was examined in 20 fragments from a genomic DNA library constructed using phage EMBL3. Five fragments apparently contained full 9.35 kbp elements while in 11 del was recovered in part. Two clones carried tandem arrangements of del, with single LTRs and internal sequences alternating, and one insert contained a solo LTR. Evidence suggests that these arrangements, which can arise by unequal crossing over, have a genomic rather than a cloning origin. Finally, one cloned fragment had a complex del arrangement yet to be fully defined. Limited sequencing of five LTRs (from a full del, a tandem arrangement and a solo LTR) indicates that the consensus termini are 5'TGT...ACA3', with del sequences flanked by a 5 bp tandem repeat. Thus del shares properties with retrotransposons such as the copia family of Drosophila and Ty of yeast. However with more than 13,000 copies per genome it seems del has been amplified more than is usual for such elements.
从川百合的大基因组中鉴定出一个9.35千碱基对（kbp）的元件，其具有2.4千碱基对的长末端正向重复序列（LTRs）。利用噬菌体EMBL3构建基因组DNA文库，从20个片段中检测了名为del的元件的结构。5个片段显然包含完整的9.35千碱基对元件，而在11个片段中部分回收了del。两个克隆携带del的串联排列，单个LTR和内部序列交替出现，一个插入片段包含一个单独的LTR。有证据表明，这些可通过不等交换产生的排列具有基因组起源而非克隆起源。最后，一个克隆片段具有复杂的del排列，尚未完全确定。对5个LTR（来自一个完整的del、一个串联排列和一个单独的LTR）的有限测序表明，共有末端为5'TGT...ACA3'，del序列两侧有一个5碱基对的串联重复序列。因此，del与逆转座子具有共同特性，如果蝇的copia家族和酵母的Ty。然而，每个基因组中有超过13000个拷贝，似乎del的扩增比此类元件通常的情况更为频繁。
