Unusual strategies of gene expression and control in parasites.
Unusual strategies of gene expression and control in parasites.
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寄生虫基因表达和控制的不寻常策略。
作者：
Timothy W. Nilsen
与高等真核生物相比，寄生线虫的mRNA成熟机制和基因调控方式有很大的不同。这些机制的细节主要来自锥虫体外研究中的植物群和无细胞系统的体外操作。来源于寄生线虫蛔虫（Ascaris lumbricoides）。第一个真核多顺反子转录单位是在隐孢子虫中发现的，它们也表现出反式剪接：杆状RNA编辑（参见Simpson和Maslov的随附观点）。与其他真核生物的转录调控不同，这些生物的基因调控主要是由转录后机制决定的。初看起来，锥虫的mRNA与标准的真核生物的mRNA没有区别。它具有侧翼为5'和Y非翻译区的单个编码序列; 5'端被加帽，3'端被聚腺苷酸化。然而，这种RNA的生物学特征与大多数真核生物中的d-at在各个方面都不同。锥虫基因表现出一种eccenmc模式的转录：这些生物体是不寻常的，因为它们包含了许多串联阵列的紧密间隔的基因（I），似乎不包含启动子元件内或在其序列的末端。这些发现，加上短波长紫外光灭活研究和随后的转染实验，已经清楚地确定，大多数蛋白质编码基因是作为多顺反子初级转录本的一部分合成的（1）。成熟mRNA的产生需要从初级转录物中切除各个编码序列及其相关的非翻译区。这是通过两个RNA加工反应完成的：分子间（u-ans）剪接和多聚腺苷酸化。“我通过一种不寻常的RNA加工反应进行了转剪接，这种反应精确地将植物群的外显子分离出来（2，3）。如前所述，锥虫（和其它生物体）中的剪接与其它真核生物中从核转录-mRNA中切除内含子的过程密切相关。trans-j21 i的subsuates是一个小的非-
S~mae parasites display highh unusual mechanisms of mRNA maturation and modes of gene regulation m comparison to those ~f higher eukary~tes. The details et these mechanisms have come primarily flora in vlvo studies m rbe trypanosomids and in vilro manipularion of cell-free system., derived from tl~e parasitic nematode Ascaris lumbricoides. The first eukaryotic muhicistronic transcription units were found in lrypanosomatids, and they also exhibit trans-splicing, :rod RNA editing {see accompanying Perspective by Simpson and Maslov). Unlike transcriptL,mal gene regulation in other eukarx.ote~, gene regulmion in dlese organisms is largely dictated by posttranscriptional mecbm~isms. At first blush, trypanosomatid mRNA appears indistinguishable from the standard eukaryotic mRNAs. It has a single c~ding sequence flanked by 5' and Y untranslated regions; the 5' ends are capped and the 3' ends are polyadenylated. Yet, the biofeenesis of this RNA differs m ahnost every respect from d~at in most eukaryotes. Trypanosomatid genes exhibit an eccenmc mode of transcription: These organisms are unusual because they contain a number of tandem arrays of closely spaced genes (I), which do not seem to contain promoter elements either within or at the extremities of their sequences. These findings, coupled with short-wavelength ultraviolet light inactivation studies and subsequent transfection experiments, have clearly established that most protein-coding genes are synthesized as part of multicistronic primary transcripts (1). The generation of mature mRNA requires that individual coding sequences and their associated untranslated regions be excised from the primary transcript. This is accomplished by two RNA-processing reactions: mtermolecular (u-ans)-splicing and polyadenylation. "I rans-splic ing ib an unusual RNA processing reaction that preciseh jtm~s exons derwed flora separate lrans~ripts (2, 3). As discussed l~elow, trans.,plicing in trypanos~mlatids (and other organisms) is closely related to the process whereby mtrons are excised from nuclear pw-mRNAs in other eukaryotes. The subsuates of trans-~j21i£ing are a small non-
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参与锥虫转拼的 U snRNA 的体内紫外交联。
影响因子：
10.5
作者：
Watkins,KP;Agabian,N
通讯作者：
Agabian,N
影响因子：
56.9
作者：
HANNON, GJ;MARONEY, PA;NILSEN, TW
通讯作者：
NILSEN, TW
3-非翻译区在布氏锥虫发育调节中的可能作用。
影响因子：
1.5
作者：
Hug,M;Carruthers,VB;Hartmann,C;Sherman,DS;Cross,GA;Clayton,C
通讯作者：
Clayton,C
影响因子：
10.5
作者：
LEBOWITZ, JH;SMITH, HQ;BEVERLEY, SM
通讯作者：
BEVERLEY, SM
DOI：
10.1073/pnas.87.22.8879
发表时间：
1990-11-01
影响因子：
11.1
作者：
RAJKOVIC, A;DAVIS, RE;ROTTMAN, FM
通讯作者：
ROTTMAN, FM