Identification of a repeated sequence in the genome of the sea urchin which is transcribed by RNA polymerase III and contains the features of a retroposon.
Identification of a repeated sequence in the genome of the sea urchin which is transcribed by RNA polymerase III and contains the features of a retroposon.
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鉴定海胆基因组中的重复序列，该序列由 RNA 聚合酶 III 转录并包含反座子的特征。
DOI：
10.1093/nar/16.4.1431
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发表时间：
1988
影响因子：
14.9
通讯作者：
CrainJr,WR
中科院分区：
文献类型：
--
作者：
Nisson,PE;Hickey,RJ;Boshar,MF;CrainJr,WR
位于海胆（Strongylocentrotus purpuratus）基因组中肌肉肌动蛋白基因的蛋白质编码部分上游约 200 个核苷酸（可能在一个大的 5' 内含子内）的重复序列元件已被表征，并显示其包含序列特征，表明它已通过 RNA 中间体转座。这种反座子样序列 SURF1-1 是一个家族的成员，该家族在基因组中分散并重复约 800 次，称为 SURF1（海胆反座子家族 1）。通过 RNA 聚合酶 III 对该序列进行体外转录，定义了一个 300 个核苷酸的转录单位，该单位由短直接重复序列界定。该单元的 3' 端包含反座子特有的简单 21 个核苷酸的富含 A+T 的序列，内部 RNA 聚合酶 III 启动子的共有 B 盒部分位于两个转录起始位点下游 60 至 80 个核苷酸处。该序列还包含一个与多个 tRNA 序列（包含 B 盒）相关的 40 个核苷酸区域，以及一个与之前显示存在于该物种 Spec1 和 Spec2 mRNA 3' 非翻译部分内的重复序列同源的 79 个核苷酸序列 (1)。对几个胚胎阶段 RNA 中该序列家族转录本的分析表明，其表达在受精后 11 小时（约 128 个细胞）时最高，并随着发育的进行而下降。此外，从11小时胚胎分离的细胞核中该序列家族的大部分或全部转录是通过RNA聚合酶III进行的，并且来自体外转录的同一链。
A repeated sequence element which is located about 200 nuoleotides upstream from the protein-coding portion of the muscle actin gene (probably within a large 5′ intron) in the genome of the sea urchin,Strongylocentrotus purpuratushas been characterized, and shown to contain the sequence features which indicate that it has been transposed by means of an RNA intermediate. This retroposon-like sequence, SURF1-1, is a member of a family which is dispersed and repeated about 800 times in the genome, referred to as SURF1 (sea urchin retroposon family 1).Invitrotranscription of this sequence by RNA polymerase III defines a 300 nucleotide transcription unit which is bounded by a short direct repeated sequence. The 3′ end of this unit contains a simple 21 nucleotide A+T−rich sequence characteristic of retroposons, and a consensus B box portion of an internal RNA polymerase III promotor is located 60 to 80 nucleotides downstream from the two sites of transcription initiation. This sequence also contains a 40 nuoleotide region that is related to several tRNA sequences (containing the B box), and a 79 nuoleotide sequence which is homologous to a repeated sequence previously shown to be present within the 3′ untranslated portions of the Spec1 and Spec2 mRMAs of this species (1). Analysis of transcripts of this sequence family in RNA from several embryonic stages indicates that its expression is highest at 11 hours postfertilization (about 128 cells) and drops as development procedes. Furthermore, most or all, transcription of this sequence family in nuclei isolated from 11 hour embryos is by RNA polymerase III, and is from the same strand which is transcribedinvitro.