Trypanosoma cruzi mitochondrial maxicircles display species- and strain-specific variation and a conserved element in the non-coding region.
Trypanosoma cruzi mitochondrial maxicircles display species- and strain-specific variation and a conserved element in the non-coding region.
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DOI：
10.1186/1471-2164-7-60
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发表时间：
2006-03-22
期刊：
影响因子：
4.4
通讯作者：
Sturm NR
中科院分区：
文献类型：
--
作者：
Westenberger SJ;Cerqueira GC;El-Sayed NM;Zingales B;Campbell DA;Sturm NR
动质体鞭毛虫的线粒体 DNA 因其巨大的尺寸、复杂的形式和大量的序列内容而在真核世界中独一无二。动质体网络由含有 rRNA 和蛋白质编码基因的链状大环和数千个编码小向导 RNA 的异质小环组成，随着尿苷插入和删除 RNA 编辑形式的极端形式的 mRNA 加工而进化。如果没有这种转录后序列修饰，许多大环编码的 mRNA 就无法翻译。我们展示了 CL Brener 和 Esmeraldo 品系克氏锥虫上环的完整序列和注释。基因顺序与布氏锥虫和塔伦托利什曼原虫同线。非编码组件具有菌株特异性重复区和每个菌株独特的可变区，除了可作为复制起点的保守序列元件之外，但与 L. tarentolae 或 T. brucei 没有序列同一性。可变区的替代组装证明了大圆群体的菌株内异质性。特定基因所需的 mRNA 编辑程度与 T. brucei 中所见的程度相似。与未编辑的基因和 rRNA 基因相比，广泛编辑的基因在属之间的差异更大。 Esmeraldo 包含一个独特的 236 bp 缺失，删除了 ND4 和 CR4 的 5' 端以及基因间区域。 Esmeraldo 在 ND5、MURF1 和 MURF2 中显示出其他物种编辑区域之外的额外插入和删除，而 CL Brener 在 MURF2 中具有明显的插入。 CL Brener 和 Esmeraldo maxicircles 代表了先前定义的三个 maxicircle 分支中的两个，并有望作为分类标记。被破坏的阅读框的恢复可以通过菌株特异性 RNA 编辑来完成。非编码区中的元件对于动质体网络内的大环的复制、转录和锚定可能很重要。
The mitochondrial DNA of kinetoplastid flagellates is distinctive in the eukaryotic world due to its massive size, complex form and large sequence content. Comprised of catenated maxicircles that contain rRNA and protein-coding genes and thousands of heterogeneous minicircles encoding small guide RNAs, the kinetoplast network has evolved along with an extreme form of mRNA processing in the form of uridine insertion and deletion RNA editing. Many maxicircle-encoded mRNAs cannot be translated without this post-transcriptional sequence modification. We present the complete sequence and annotation of the Trypanosoma cruzi maxicircles for the CL Brener and Esmeraldo strains. Gene order is syntenic with Trypanosoma brucei and Leishmania tarentolae maxicircles. The non-coding components have strain-specific repetitive regions and a variable region that is unique for each strain with the exception of a conserved sequence element that may serve as an origin of replication, but shows no sequence identity with L. tarentolae or T. brucei. Alternative assemblies of the variable region demonstrate intra-strain heterogeneity of the maxicircle population. The extent of mRNA editing required for particular genes approximates that seen in T. brucei. Extensively edited genes were more divergent among the genera than non-edited and rRNA genes. Esmeraldo contains a unique 236-bp deletion that removes the 5'-ends of ND4 and CR4 and the intergenic region. Esmeraldo shows additional insertions and deletions outside of areas edited in other species in ND5, MURF1, and MURF2, while CL Brener has a distinct insertion in MURF2. The CL Brener and Esmeraldo maxicircles represent two of three previously defined maxicircle clades and promise utility as taxonomic markers. Restoration of the disrupted reading frames might be accomplished by strain-specific RNA editing. Elements in the non-coding region may be important for replication, transcription, and anchoring of the maxicircle within the kinetoplast network.
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影响因子：
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