Integrated mapping, chromosomal sequencing and sequence analysis of Cryptosporidium parvum
Integrated mapping, chromosomal sequencing and sequence analysis of Cryptosporidium parvum
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DOI：
10.1101/gr.1555203
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发表时间：
2003-08-01
期刊：
影响因子：
7
通讯作者：
Dear, PH
中科院分区：
文献类型：
--
作者：
Bankier, AT;Spriggs, HF;Dear, PH
顶端复门隐孢子虫是人类最常见的原生动物寄生虫之一。我们报告了爱荷华分离株基因组的物理作图、6 号染色体的测序和分析，以及从基因组其余部分采样的类似 0.9 Mbp 的序列。为了构建强大的物理图，我们设计了一种新颖且通用的策略，无论克隆制品如何，都能够准确放置克隆。分析揭示了一个紧凑的基因组，膜蛋白异常丰富。与恶性疟原虫一样，预测蛋白质的平均大小大于其他已测序的真核生物。我们发现了几种预测的感兴趣的蛋白质作为潜在的治疗靶点，其中一种与疟原虫的氯喹抗性蛋白表现出相似性。编码序列分析反对隐孢子虫的传统系统发育位置，并支持早期的建议，即该属起源于顶复门内的早期分支。与此一致的是，我们发现与疟原虫没有显着的同线性，并且令人惊讶地很少有蛋白质相似性。最后，我们在整个基因组中发现了两个不寻常且丰富的重复序列。在已测序的基因组中，一个基序仅在微小球虫中丰富，而另一个基序与所有已知的球虫和血孢子虫基因组共有（但之前未被注意到）。这些图案在结构、分布和序列方面似乎是独特的。
The apicomplexan Cryptosporidium parvum is one of the most prevalent protozoan parasites of humans. We report the physical mapping of the genome of the Iowa isolate, sequencing and analysis of chromosome 6, and similar to0.9 Mbp of sequence sampled from the remainder of the genome. To construct a robust physical map, we devised a novel and general strategy, enabling accurate placement of clones regardless of clone artefacts. Analysis reveals a compact genome, unusually rich in membrane proteins. As in Plasmodium falciparum, the mean size of the predicted proteins is larger than that in other sequenced eukaryotes. We find several predicted proteins of interest as potential therapeutic targets, including one exhibiting similarity to the chloroquine resistance protein of Plasmodium. Coding sequence analysis argues against the conventional phylogenetic position of Cryptosporidium and supports an earlier suggestion that this genus arose from an early branching within the Apicomplexa. In agreement with this, we find no significant synteny and surprisingly little protein similarity with Plasmodium. Finally, we find two unusual and abundant repeats throughout the genome. Among sequenced genomes, one motif is abundant only in C parvum, whereas the other is shared with (but has previously gone unnoticed in) all known genomes of the Coccidia and Haemosporida. These motifs appear to be unique in their structure, distribution and sequences.