Impact of small repeat sequences on bacterial genome evolution.
Impact of small repeat sequences on bacterial genome evolution.
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DOI：
10.1093/gbe/evr077
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发表时间：
2011
影响因子：
3.3
通讯作者：
Delihas N
中科院分区：
文献类型：
--
作者：
Delihas N
原核生物基因组的基因间区携带着末端倒置重复序列（TIR）的多个拷贝，这是一种非自主微型倒置重复转座元件（MITE）。此外，还有重复的基因外回文（REP）序列，它们折叠成一个富含G-C键的小茎环。聚集在一起的规律间隔的短回文重复序列（crispr）显示出类似的小茎环，但却是复杂遗传元素的组成部分。其他类的重复（如REP2元素）没有tir，但显示其他签名。随着目前大量全基因组序列的可用性，许多新的重复元件被发现。这些序列显示出不同的特性。有些显示出与整合子的密切联系，至少有一个编码小RNA。发现许多重复序列与染色体开放阅读框融合，有些位于蛋白质编码序列中。小的重复单元似乎与细胞的转录和/或转录后装置携手合作。从功能上讲，它们是多方面的，可以控制基因表达，促进宿主/病原体相互作用，或刺激哺乳动物免疫系统。CRISPR复合体显示出惊人的功能，比如获得性免疫系统，可以抵御入侵的病毒和质粒。在进化上，移动重复元件可能影响了祖先生物中活性与非活性基因的循环，并且一些重复元件集中在染色体上具有显著基因组可塑性的区域。在生物体进化过程中，基因组重复序列丰度的变化可能对细胞有利，也可能对细胞不利，一些现存物种可能反映了纯化过程。描述了重复元素的多样结构、兼收并蓄的功能和演化方面。
Intergenic regions of prokaryotic genomes carry multiple copies of terminal inverted repeat (TIR) sequences, the nonautonomous miniature inverted-repeat transposable element (MITE). In addition, there are the repetitive extragenic palindromic (REP) sequences that fold into a small stem loop rich in G–C bonding. And the clustered regularly interspaced short palindromic repeats (CRISPRs) display similar small stem loops but are an integral part of a complex genetic element. Other classes of repeats such as the REP2 element do not have TIRs but show other signatures. With the current availability of a large number of whole-genome sequences, many new repeat elements have been discovered. These sequences display diverse properties. Some show an intimate linkage to integrons, and at least one encodes a small RNA. Many repeats are found fused with chromosomal open reading frames, and some are located within protein coding sequences. Small repeat units appear to work hand in hand with the transcriptional and/or post-transcriptional apparatus of the cell. Functionally, they are multifaceted, and this can range from the control of gene expression, the facilitation of host/pathogen interactions, or stimulation of the mammalian immune system. The CRISPR complex displays dramatic functions such as an acquired immune system that defends against invading viruses and plasmids. Evolutionarily, mobile repeat elements may have influenced a cycle of active versus inactive genes in ancestral organisms, and some repeats are concentrated in regions of the chromosome where there is significant genomic plasticity. Changes in the abundance of genomic repeats during the evolution of an organism may have resulted in a benefit to the cell or posed a disadvantage, and some present day species may reflect a purification process. The diverse structure, eclectic functions, and evolutionary aspects of repeat elements are described.
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影响因子：
3.2
作者：
De Gregorio, Eliana;Silvestro, Giustina;Di Nocera, Pier Paolo
通讯作者：
Di Nocera, Pier Paolo
影响因子：
3.2
作者：
Choi, S;Ohta, S;Ohtsubo, E
通讯作者：
Ohtsubo, E
DOI：
10.1126/science.1159689
发表时间：
2008-08-15
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Brouns SJ;Jore MM;Lundgren M;Westra ER;Slijkhuis RJ;Snijders AP;Dickman MJ;Makarova KS;Koonin EV;van der Oost J
通讯作者：
van der Oost J
影响因子：
3.2
作者：
Chen, SL;Shapiro, L
通讯作者：
Shapiro, L
影响因子：
14.9
作者：
Chinni SV;Raabe CA;Zakaria R;Randau G;Hoe CH;Zemann A;Brosius J;Tang TH;Rozhdestvensky TS
通讯作者：
Rozhdestvensky TS