Phylogenetic analysis and possible function of bro-like genes, a multigene family widespread among large double-stranded DNA viruses of invertebrates and bacteria
Phylogenetic analysis and possible function of bro-like genes, a multigene family widespread among large double-stranded DNA viruses of invertebrates and bacteria
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DOI：
10.1099/vir.0.19256-0
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发表时间：
2003-09-01
影响因子：
3.8
通讯作者：
Bigot, Y
中科院分区：
文献类型：
--
作者：
Bideshi, DK;Renault, S;Bigot, Y
杆状病毒重复开放阅读框架(Bro)基因及其近缘基因构成一个多基因家族，通常每个基因组有多个拷贝，已知存在于某些昆虫dsDNA病毒和噬菌体中。人们对这些基因编码的蛋白质的进化历史和功能知之甚少。在这里，我们已经证明了bro和bro-like(bro-L)基因存在于另外两个无脊椎动物病毒科，Ascoviridae和Iridoviridae，以及原核生物的第II类转座子中。对100多个序列的分析表明，N-末端区域由两个亚区组成，是最保守的区域，包含一个先前描述的DNA结合基序。系统进化分析表明，这些蛋白质分布在8个类群中，第1-7类由无脊椎动物病毒蛋白组成，第8类由噬菌体和细菌转座子中的蛋白质组成。在无脊椎动物或脊椎动物基因组数据库、脊椎动物病毒和转座子数据库中没有发现bro基因，在原核生物基因组中也没有发现bro基因，除了后者的前噬菌体或转座子。Bro基因之间的系统发育关系表明，它们是病毒基因组重组的结果，允许基因复制和丢失，但也是随着进化时间的推移通过水平转移获得基因的结果。此外，Bro-L基因在不同类型的无脊椎动物双链DNA病毒中的维持和多样性，而在脊椎动物病毒中不存在，表明这些蛋白在无脊椎动物病毒生物学中发挥着重要作用。对褐斑潜蝇核型多角体病毒特有的ort2bro基因的实验表明，该基因不是复制所必需的，但可能在繁殖的闭锁阶段促进复制。
Baculovirus repeated open reading frame (bro) genes and their relatives constitute a multigene family, typically with multiple copies per genome, known to occur among certain insect dsDNA viruses and bacteriophages. Little is known about the evolutionary history and function of the proteins encoded by these genes. Here we have shown that bro and bro-like (bro-l) genes occur among viruses of two additional invertebrate viral families, Ascoviridae and Iridoviridae, and in prokaryotic class II transposons. Analysis of over 100 sequences showed that the N-terminal region, consisting of two subdomains, is the most conserved region and contains a DNA-binding motif that has been characterized previously. Phylogenetic analysis indicated that these proteins are distributed among eight groups, Groups 1-7 consisting of invertebrate virus proteins and Group 8 of proteins in bacteriophages and bacterial transposons. No bro genes were identified in databases of invertebrate or vertebrate genomes, vertebrate viruses and transposons, nor in prokaryotic genomes, except in prophages or transposons of the latter. The phylogenetic relationship between bro genes suggests that they have resulted from recombination of viral genomes that allowed the duplication and loss of genes, but also the acquisition of genes by horizontal transfer over evolutionary time. In addition, the maintenance and diversity of bro-l genes in different types of invertebrate dsDNA viruses, but not in vertebrate viruses, suggests that these proteins play an important role in invertebrate virus biology. Experiments with the unique ort2 bro gene of Autographa californica multicapsid nucleopolyhedrovirus showed that it is not required for replication, but may enhance replication during the occlusion phase of reproduction.