Subfamilies of CR1 non-LTR retrotransposons have different 5′UTR sequences but are otherwise conserved
Subfamilies of CR1 non-LTR retrotransposons have different 5′UTR sequences but are otherwise conserved
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DOI：
10.1016/s0378-1119(01)00344-4
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发表时间：
2001-03-07
期刊：
影响因子：
3.5
通讯作者：
Burch, JBE
中科院分区：
文献类型：
--
作者：
Haas, NB;Grabowski, JM;Burch, JBE
CR1元件和CR1相关(CR1-like)元件是一个新的非LTR反转录转座子家族，在所有脊椎动物(爬行动物、两栖动物、鱼类和哺乳动物)中都有发现，而在一些无脊椎动物中发现了更远的亲缘元件。CRI元件有几个区别于其他非LTR反转录转座子的特征。最值得注意的是，它们的3‘末端缺少多聚腺苷酸(PolyA)尾巴，而是含有2-4个拷贝的独特的8个核苷酸重复序列。CR1元件在鸡基因组中的存在类似于100.000个拷贝。这些元件中的绝大多数被严重的5‘端截断和突变；然而，通过序列比较决定了六个亚家族(CR1-A到CR1-F)。其中一个亚家族(即CR1-B)已被详细分析过。在本研究中，我们从CR1-F亚家族中鉴定了几个全长元件。尽管开放阅读框内的区域和CR1-F和CR1-B元件的3‘非翻译区被很好地保存下来，但它们各自的5’非翻译区是不相关的。因此，我们的结果表明，当开放阅读框完整的元件获得新的5‘UTRs时，新的CR1亚家族就会形成，原则上，这些UTRs可以作为启动子发挥作用。(C)2001 Elsevier Science B.V.保留所有权利。
CR1 elements and CR1-related (CR1-like) elements are a novel family of non-LTR retrotransposons that are found in all vertebrates (reptilia, amphibia, fish, and mammals), whereas more distantly related elements are found in several invertebrate species. CRI elements have several features that distinguish them from other non-LTR retrotransposons. Most notably, their 3' termini lack a polyadenylic acid (poly A) tail and instead contain 2-4 copies of a unique 8 bp repeat. CR1 elements are present at similar to 100.000 copies in the chicken genome. The vast majority of these elements are severely 5' truncated and mutated; however, six subfamilies (CR1-A through CR1-F) are resolved by sequence comparisons. One of these subfamilies (i.e. CR1-B) previously was analyzed in detail. In the present study, we identified several full-length elements from the CR1-F subfamily. Although regions within the open reading frames and 3' untranslated regions of CR1-F and CR1-B elements ore well conserved, their respective 5' untranslated regions are unrelated. Thus, our results suggest that new CR1 subfamilies form when elements with intact open reading frames acquire new 5'UTRs, which could, in principle, function as promoters. (C) 2001 Elsevier Science B.V. All rights reserved.