Functional reverse transcriptases encoded by A-type mouse LINE-1: defining the minimal domain by deletion analysis.
Functional reverse transcriptases encoded by A-type mouse LINE-1: defining the minimal domain by deletion analysis.
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A 型小鼠 LINE-1 编码的功能性逆转录酶：通过删除分析定义最小结构域。
DOI：
10.1016/s0378-1119(98)00252-2
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发表时间：
1998
期刊：
影响因子：
3.5
通讯作者：
Lieberman,B
中科院分区：
文献类型：
--
作者：
Martin,SL;Li,J;Epperson,LE;Lieberman,B
长散布元件（long interspersed elements，LINE）是通过RNA中间体移动的反转录转座子。在小鼠中，L1的一种多态性变体最近扩增，在属于Mus属和亚属的物种中产生A型亚科。LINE-1（L1）的逆转录转座需要由开放阅读框2（ORF 2）产生的L1编码的逆转录酶的功能。在这里，我们采用了一种方便的酵母遗传分析，以确定从三个A型L1元件获得的ORF2的逆转录酶活性：一个，从核糖核蛋白颗粒中的RNA的cDNA;另一个与一个所谓的失活突变;和第三个，一个假设的祖先构建。因为没有最近转座到p53基因的A型元件的例子，所以该测定是证明小鼠A型LINE-1元件的功能能力的第一步。据信，这三个元件中的一个在进化过程中被亮氨酸取代为已知逆转录酶中高度保守的苯丙氨酸或色氨酸残基而失活。在酵母试验中，该突变未抑制L1逆转录酶;因此，检测的所有三种元件均编码逆转录酶活性。我们通过创建一系列缺失进一步检查了ORF2内的最小逆转录酶结构域。结果表明，从ORF2的N-末端区域去除L1核酸内切酶结构域不会影响逆转录酶活性，如本试验所确定的，并且功能性逆转录酶需要来自小鼠A型L1元件的ORF2编码序列的大约一半。
Long interspersed elements, or LINEs, are retrotransposons that move via an RNA intermediate. In mice, one polymorphic variant of L1 has amplified relatively recently, giving rise to the A-type subfamily in species belonging to the genus and subgenus Mus. Retrotransposition of LINE-1 (L1) requires the function of the L1-encoded reverse transcriptase that is produced from open reading frame 2 (ORF2). Here, we employ a convenient yeast genetic assay to determine the reverse transcriptase activity of the ORF2 obtained from three A-type L1 elements: one, a cDNA from the RNA in ribonucleoprotein particles; another with a purported inactivating mutation; and the third, a hypothetical ancestral construct. Because there are no examples of A-type elements that have transposed recently to inactivate a gene, this assay is the first step towards demonstrating the functional capability of mouse A-type LINE-1 elements. One of the three elements was believed to have been inactivated during evolution by the substitution of leucine for a highly conserved phenylalanine or tryptophan residue among known reverse transcriptases. This mutation did not inactivate the L1 reverse transcriptase in the yeast assay; thus, all three of the elements tested encoded reverse transcriptase activity. We further examined the minimal reverse transcriptase domain within ORF2 by creating a series of deletions. The results demonstrate that removal of the L1 endonuclease domain from the N-terminal region of ORF2 does not affect reverse transcriptase activity as determined by this assay, and that approximately half of the ORF2 coding sequence from mouse A-type L1 elements is required for functional reverse transcriptase.
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小鼠 F9 细胞中链特异性 LINE-1 转录源自 LINE-1 元件最年轻的系统发育亚组。
影响因子：
5.6
作者：
Schichman,SA;Severynse,DM;Edgell,MH;Hutchison3rd,CA
通讯作者：
Hutchison3rd,CA
影响因子：
11.4
作者：
Hohjoh, H;Singer, MF
通讯作者：
Singer, MF
功能性祖先序列的确定和 A 型小鼠 L1 元件 5 端的定义。
影响因子：
5.6
作者：
Shehee,WR;Chao,SF;Loeb,DD;Comer,MB;Hutchison3rd,CA;Edgell,MH
通讯作者：
Edgell,MH
影响因子：
56.9
作者：
Nakamura, TM;Morin, GB;Cech, TR
通讯作者：
Cech, TR
DOI：
10.1073/pnas.94.19.10155
发表时间：
1997-09-16
影响因子：
11.1
作者：
Kolosha, VO;Martin, SL
通讯作者：
Martin, SL