Stripped-down DNA repair in a highly reduced parasite.
Stripped-down DNA repair in a highly reduced parasite.
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DOI：
10.1186/1471-2199-8-24
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发表时间：
2007-03-20
影响因子：
--
通讯作者：
Fast, Naomi M.
中科院分区：
文献类型：
--
作者：
Gill, Erin E.;Fast, Naomi M.
楔形脑孢子虫是一组独特的单细胞寄生真核生物的成员，称为微孢子虫，与真菌关系密切。其中一些生物，包括海藻，也有在原核生物范围内的独特的小基因组。因此，小球藻经历了大规模的基因组减少，导致了不同生物途径的基因丢失，包括那些作用于DNA修复的基因。DNA修复对任何活细胞都是必不可少的。这些机制的丧失必然会导致突变的积累和/或细胞死亡。真核生物DNA修复的六条主要途径包括：非同源末端连接(NHEJ)、同源重组修复(HRR)、错配修复(MMR)、核苷酸切除修复(NER)、碱基切除修复(BER)和甲基转移酶修复。DNA聚合酶也是DNA修复过程中的关键角色。鉴于微孢子虫和真菌之间的密切关系，我们比较了楔形微孢子虫和酵母的修复机制，以确定基因组减少的过程是如何影响DNA修复途径的。通过BLASTP和PSI-BLAST搜索寻找的56个DNA修复基因中，有16个缺失(加上另外6个潜在缺失)。14个DNA聚合酶或聚合酶亚基中也有6个在楔形艾美耳球虫中缺失。所有这些基因在真核生物中都相对保守。基因缺失在不同的修复途径中的分布并不均匀；有些修复途径只缺少一种蛋白质，而作为两条双链断裂修复途径的组成部分的许多蛋白质也明显缺乏。所有专门的修复聚合酶也都不存在。由于在双链断裂修复途径中缺少大量的DNA修复基因，因此利用最少的机械来研究双链断裂修复是一种理想的候选方法。令人惊讶的是，所有被楔形艾美耳球虫保留的双链断裂修复基因都参与了其他生物途径。
Encephalitozoon cuniculi is a member of a distinctive group of single-celled parasitic eukaryotes called microsporidia, which are closely related to fungi. Some of these organisms, including E. cuniculi, also have uniquely small genomes that are within the prokaryotic range. Thus, E. cuniculi has undergone a massive genome reduction which has resulted in a loss of genes from diverse biological pathways, including those that act in DNA repair. DNA repair is essential to any living cell. A loss of these mechanisms invariably results in accumulation of mutations and/or cell death. Six major pathways of DNA repair in eukaryotes include: non-homologous end joining (NHEJ), homologous recombination repair (HRR), mismatch repair (MMR), nucleotide excision repair (NER), base excision repair (BER) and methyltransferase repair. DNA polymerases are also critical players in DNA repair processes. Given the close relationship between microsporidia and fungi, the repair mechanisms present in E. cuniculi were compared to those of the yeast Saccharomyces cerevisiae to ascertain how the process of genome reduction has affected the DNA repair pathways. E. cuniculi lacks 16 (plus another 6 potential absences) of the 56 DNA repair genes sought via BLASTP and PSI-BLAST searches. Six of 14 DNA polymerases or polymerase subunits are also absent in E. cuniculi. All of these genes are relatively well conserved within eukaryotes. The absence of genes is not distributed equally among the different repair pathways; some pathways lack only one protein, while there is a striking absence of many proteins that are components of both double strand break repair pathways. All specialized repair polymerases are also absent. Given the large number of DNA repair genes that are absent from the double strand break repair pathways, E. cuniculi is a prime candidate for the study of double strand break repair with minimal machinery. Strikingly, all of the double strand break repair genes that have been retained by E. cuniculi participate in other biological pathways.
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影响因子：
5.3
作者：
Aylon, Y;Liefshitz, B;Kupiec, M
通讯作者：
Kupiec, M
影响因子：
5.3
作者：
Aylon, Y;Kupiec, M
通讯作者：
Kupiec, M
DOI：
10.1007/bf00330657
发表时间：
1983-01-01
期刊：
MOLECULAR AND GENERAL GENETICS
影响因子：
--
作者：
JOHNSTON, LH
通讯作者：
JOHNSTON, LH
影响因子：
3
作者：
Keeling, PJ
通讯作者：
Keeling, PJ
影响因子：
64.8
作者：
James, Timothy Y.;Kauff, Frank;Vilgalys, Rytas
通讯作者：
Vilgalys, Rytas