Structure of the micronuclear α-tubulin gene in the phyllopharyngean ciliate Chilodonella uncinata:: implications for the evolution of chromosomal processing
Structure of the micronuclear α-tubulin gene in the phyllopharyngean ciliate Chilodonella uncinata:: implications for the evolution of chromosomal processing
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DOI：
10.1016/j.gene.2003.08.003
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发表时间：
2003-10-02
期刊：
影响因子：
3.5
通讯作者：
Snoeyenbos-West, OLO
中科院分区：
文献类型：
--
作者：
Katz, LA;Lasek-Nesselquist, E;Snoeyenbos-West, OLO
纤毛虫是一类具有二型核的微生物真核生物，每个细胞都含有一个转录活性大核和一个生殖细胞微核。在大核的发育过程中，生殖细胞染色体通过广泛的片段化、去除内部切除序列（IES）和DNA扩增而重排。我们的特点是三个IES的基因编码α-微管蛋白的phyllopharyngean纤毛虫Chilodonella uncinata。IEs位于编码结构域内，大小范围为81至107 bp，侧翼为长度为6至8 bp的同向重复序列。所有三个IES都是适度AT丰富的，每个都包含两个拷贝的保守序列基序。这些数据为叶咽类纤毛虫中存在IES提供了证据，并表明C。uncinata可能依赖于一个新的顺式作用序列。与C.与“模式”纤毛虫草履虫属、四膜虫属、游仆虫属、尖毛虫属和柱尾虫属的染色体比较，显示出纤毛虫染色体加工的显著差异。(C)2003 Elsevier B. V.保留所有权利。
Ciliates are a group of microbial eukaryotes defined by the presence of dimorphic nuclei-each cell contains both a transcriptionally active macronucleus and a germline micronucleus. During the development of the macronucleus, germline chromosomes are rearranged through extensive fragmentation, removal of internally excised sequences (IESs) and DNA amplification. We have characterized three IESs in the gene that encodes alpha-tubulin in the phyllopharyngean ciliate Chilodonella uncinata. The IESs are located within the coding domain, range in size from 81 to 107 bp, and are flanked by direct repeats that vary in length from 6 to 8 bp. All three IESs are moderately AT-rich and each contains two copies of a conserved sequence motif. These data provide evidence for the existence of IESs in phyllopharyngean ciliates and suggest that IES processing in C. uncinata may rely on a novel cis-acting sequence. Comparisons of the IESs in C. uncinata with those of 'model' ciliates-Paramecium, Tetrahymena, Euplotes, Oxytricha and Stylonychia-reveal considerable variation in chromosomal processing among ciliates. (C) 2003 Elsevier B.V. All rights reserved.