The lambda red proteins promote efficient recombination between diverged sequences: implications for bacteriophage genome mosaicism.
The lambda red proteins promote efficient recombination between diverged sequences: implications for bacteriophage genome mosaicism.
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DOI：
10.1371/journal.pgen.1000065
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发表时间：
2008-05-02
期刊：
影响因子：
4.5
通讯作者：
Petit MA
中科院分区：
文献类型：
--
作者：
Martinsohn JT;Radman M;Petit MA
温带细菌病毒（噬菌体）的基因组嵌合体是如此之大，以至于它在基因组水平上模糊了它们的系统发育。然而，这种镶嵌现象背后的精确分子过程尚不清楚。非法重组已被提出，但同源重组也可能在起作用。为了验证这一点，我们测量了插入λ的分散的oxa基因对之间同源重组的效率。当病毒Red Gam途径激活时，分离基因之间的重组量高达22%，而当宿主大肠杆菌RecABCD途径激活时，分离基因的重组量则低100倍。重组编辑蛋白MutS和UvrD对λ重组仅表现出边际效应。因此，逃避宿主编辑有助于病毒重组的高熟练度。此外，我们的生物信息学研究表明，相似的羔羊样病毒之间的同源重组创造了它们的部分嵌合。因此，我们提出，λ编码的Red和Gam蛋白重组分散DNA的显著倾向有效地促进了嵌合现象，更普遍地说，病毒基因组嵌合现象可能与Red/Gam样系统的存在存在相关性。温带细菌病毒在休眠状态和噬菌体增殖的裂解状态之间交替。在休眠状态中，病毒DNA仍然整合在宿主基因组中。温带病毒具有一种称为“马赛克”的特有基因组组织——它们包含来自相关病毒的“外来”片段。在给定病毒与其亲缘病毒之间的成对比对中，总核苷酸序列的一致性约为50%。相比之下，马赛克片段是90%到100%相同的。嵌合体是如何产生的在很大程度上是未知的，但很可能是相关的病毒在同一细菌中相遇并经历随机重组，出现了最强大的重组病毒。普遍的假设是马赛克是由非法重组形成的。我们提出并证明了另一种驱动机制，同源重组，用于相似但分散的病毒序列之间的镶嵌形成。以众所周知的大肠杆菌λ病毒为例，我们证明了这种同源重组是非常有效的。这一发现在病毒基因组进化领域具有重要意义，因为它可以解释病毒基因组的高可塑性。它也适用于生物技术领域，并揭示了病毒是有希望的载体重组基因在体内。
Genome mosaicism in temperate bacterial viruses (bacteriophages) is so great that it obscures their phylogeny at the genome level. However, the precise molecular processes underlying this mosaicism are unknown. Illegitimate recombination has been proposed, but homeologous recombination could also be at play. To test this, we have measured the efficiency of homeologous recombination between diverged oxa gene pairs inserted into λ. High yields of recombinants between 22% diverged genes have been obtained when the virus Red Gam pathway was active, and 100 fold less when the host Escherichia coli RecABCD pathway was active. The recombination editing proteins, MutS and UvrD, showed only marginal effects on λ recombination. Thus, escape from host editing contributes to the high proficiency of virus recombination. Moreover, our bioinformatics study suggests that homeologous recombination between similar lambdoid viruses has created part of their mosaicism. We therefore propose that the remarkable propensity of the λ-encoded Red and Gam proteins to recombine diverged DNA is effectively contributing to mosaicism, and more generally, that a correlation may exist between virus genome mosaicism and the presence of Red/Gam-like systems. Temperate bacterial viruses alternate between a dormant state, during which viral DNA remains integrated in the host genome, and a lytic state of phage multiplication. Temperate viruses have a characteristic genome organisation known as ‘mosaic’ – they contain ‘foreign’ segments that originate from related viruses. In pairwise alignments between a given virus and its relatives, the overall nucleotide sequence identity is around 50%. In contrast, the mosaic segments are 90% to 100% identical. How mosaics are generated is largely unknown, but it is likely that related viruses meet in the same bacterium and undergo random recombination, with emergence of the most robust recombinatory viruses. The prevalent hypothesis is that mosaics are formed by illegitimate recombination. We propose and demonstrate that an alternative driving mechanism, homologous recombination, is used for mosaic formation between similar but diverged viral sequences. Using the well known Escherichia coli λ virus as a paradigm, we show that such homeologous recombination is remarkably efficient. This finding has important implications in the field of virus genome evolution, as it may explain the high plasticity of viral genomes. It is also applicable to the field of biotechnology, and reveals viruses to be promising vectors for shuffling genes in vivo.
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DOI：
10.1073/pnas.0610149104
发表时间：
2007-05-22
影响因子：
11.1
作者：
Elez, Marina;Radman, Miroslav;Matic, Ivan
通讯作者：
Matic, Ivan
影响因子：
4.4
作者：
Gomez, A;Galic, T;Petit, MA
通讯作者：
Petit, MA
影响因子：
3.8
作者：
Junop, MS;Yang, W;Miller, JH
通讯作者：
Miller, JH
DOI：
10.1007/bf00267368
发表时间：
1980-01-01
期刊：
MOLECULAR AND GENERAL GENETICS
影响因子：
--
作者：
ARTHUR, HM;LLOYD, RG
通讯作者：
LLOYD, RG
影响因子：
5.6
作者：
Karakousis, G;Ye, N;Radding, CM
通讯作者：
Radding, CM