GENE ORGANIZATION AND TRANSCRIPTION OF TED, A LEPIDOPTERAN RETROTRANSPOSON INTEGRATED WITHIN THE BACULOVIRUS GENOME
GENE ORGANIZATION AND TRANSCRIPTION OF TED, A LEPIDOPTERAN RETROTRANSPOSON INTEGRATED WITHIN THE BACULOVIRUS GENOME
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DOI：
10.1128/mcb.10.6.3067
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发表时间：
1990-06-01
影响因子：
5.3
通讯作者：
NISSEN, MS
中科院分区：
文献类型：
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作者：
FRIESEN, PD;NISSEN, MS
在杆状病毒苜蓿银纹夜蛾核型多角体病毒的 DNA 基因组中鉴定出来自毛纹夜蛾（一种鳞翅目夜蛾）的反转录转座子 TED 的单个拷贝。整合拷贝的完整核苷酸序列（7,510 个碱基对）的测定表明 TED 属于反转录转座子家族，该家族包括果蝇元件 17.6 和吉普赛元件，因此代表了该无脊椎动物群体中第一个待鉴定的非双翅目成员。 TED 的内部部分两侧是长末端重复序列 (LTR)，由三个长开放阅读框组成，其大小和位置与脊椎动物逆转录病毒的 gag、pol 和 env 基因相当。 TED 开放阅读框 2（pol 区）的各个结构域内与双翅目元件的序列相似性最高，这些结构域在逆转录病毒中也是保守的，分别编码蛋白酶、逆转录酶和整合酶功能。 绘制 TED RNA 的 5'' 和 3'' 末端表明，LTR 具有逆转录病毒 U3-R-U5 结构组织，能够指导代表逆转录潜在底物和转座中间体的转录物的合成。丰富的 RNA 也从 5'' LTR 内的一个位点起始，该位点与晚期超表达杆状病毒基因启动子的共有基序相匹配。这种病毒样启动子在 TED 中的存在以及仅在整合到病毒基因组中后才被激活表明与杆状病毒可能存在共生关系，从而可以扩大转座子宿主范围。
A single copy of the retrotransposon TED, from the moth Trichoplusia ni (a lepidopteran noctuid), was identified within the DNA genome of the baculovirus Autographa californica nuclear polyhedrosis virus. Determination of the complete nucleotide sequence (7,510 base pairs) of the integrated copy indicated that TED belongs to the family of retrotransposons that includes Drosophila melanogaster elements 17.6 and gypsy and thus represents the first nondipteran member of this invertebrate group to be identified. The internal portion of TED, flanked by long terminal repeats (LTRs), is composed of three long open reading frames comparable in size and location to the gag, pol, and env genese of the vertebrate retroviruses. Sequence similarity with the dipteran elements was the highest within individual domains of TED open reading frame 2 (pol region) that are also conserved among the retroviruses and encode protease, reverse transcriptase, and integrase functions, respectively. Mapping the 5'' and 3'' termini of TED RNAs indicated that the LTRs have a retroviral U3-R-U5 structural organization that is capable of directing the synthesis of transcripts that represent potential substrates for reverse transcription and intermediates in transposition. Abundant RNAs were also initiated from a site within the 5'' LTR that matches the consensus motif for the promoter of late, hyperexpressed baculovirus genes. The presence of this viruslike promoter within TED and its subsequent activation only after integration within the viral genome suggest a possible symbiotic relationship with the baculovirus that could extend transposon host range.