TNT1, A MOBILE RETROVIRAL-LIKE TRANSPOSABLE ELEMENT OF TOBACCO ISOLATED BY PLANT-CELL GENETICS
TNT1, A MOBILE RETROVIRAL-LIKE TRANSPOSABLE ELEMENT OF TOBACCO ISOLATED BY PLANT-CELL GENETICS
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DOI：
10.1038/337376a0
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发表时间：
1989-01-26
期刊：
影响因子：
64.8
通讯作者：
CABOCHE, M
中科院分区：
文献类型：
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作者：
GRANDBASTIEN, MA;SPIELMANN, A;CABOCHE, M
转座元件可以通过它们在新基因座诱导突变等位基因的能力来鉴定。逆转录转座子家族被认为通过 RNA 中间体进行转座，与脊椎动物原逆转录病毒有许多相似之处1,2。在植物中，玉米 3、4、拟南芥 5 和小麦 6 中已描述了反转录转座子，而玉米 7 中则描述了非病毒反座子。然而，这些元件中的大多数被发现是非移动集成单元。在这里，我们报告了第一个烟草（Nicotiana tabacum）转座元件 Tnt1 的分离，它似乎是高等植物中最完整的移动逆转录转座子。 Tntl 在转座到烟草的硝酸还原酶 (NR) 结构基因中后被分离出来，并且通过体外选择源自烟草叶肉原生质体的细胞培养物中自发的 NR 缺陷 (NR–) 突变株系来检测转座事件。 Tntl长5,334个核苷酸，包含两个610个碱基对长的末端重复序列和一个3,984个核苷酸的开放阅读框。将 Tntl 开放阅读框编码潜力与果蝇 copia 逆转录转座子 8、酵母 Ty 逆转录转座子 9 和脊椎动物原逆转录病毒 22 的开放阅读框编码潜力进行比较，结果表明 Tntl 与 copia 密切相关，并携带已知的逆转录自主转座所需的所有功能。
Transposable elements can be identified by their ability to induce mutant alleles at new loci. The retrotransposon family is thought to transpose through an RNA intermediate and has many similarities to vertebrate proretroviruses1,2. In plants, retrotransposons have been described in maize3,4,Arabidopsis5and wheat6, and non-viral retroposons in maize7. Most of these elements, however, have been found as non-mobile integrated units. Here, we report the isolation of the first tobacco (Nicotiana tabacum) transposable element, Tnt1, which seems to be the most complete mobile retrotransposon characterized in higher plants. Tntl has been isolated after its transposition into the nitrate reductase (NR) structural gene of tobacco, and transposition events have been detected throughin vitroselection of spontaneous NR-deficient (NR–) mutant lines in cell cultures derived from tobacco mesophyll protoplasts. Tntl is 5,334 nucleotides long, contains two 610-base-pair-long terminal repeats and a single open reading frame of 3,984 nucleotides. Comparison of the Tntl open reading frame coding potential with those of theDrosophila melanogaster copiaretrotransposon8, yeast Ty retrotransposon9, and vertebrate proretroviruses22revealed that Tntl is closely related tocopiaand carries all the functions known to be required for autonomous transposition by reverse transcription.