Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Department of Microbiology, Institut Pasteur, Paris, France.
PLoS One. 2011 May 10;6(5):e19893. doi: 10.1371/journal.pone.0019893.
The Microviridae comprises icosahedral lytic viruses with circular single-stranded DNA genomes. The family is divided into two distinct groups based on genome characteristics and virion structure. Viruses infecting enterobacteria belong to the genus Microvirus, whereas those infecting obligate parasitic bacteria, such as Chlamydia, Spiroplasma and Bdellovibrio, are classified into a subfamily, the Gokushovirinae. Recent metagenomic studies suggest that members of the Microviridae might also play an important role in marine environments. In this study we present the identification and characterization of Microviridae-related prophages integrated in the genomes of species of the Bacteroidetes, a phylum not previously known to be associated with microviruses. Searches against metagenomic databases revealed the presence of highly similar sequences in the human gut. This is the first report indicating that viruses of the Microviridae lysogenize their hosts. Absence of associated integrase-coding genes and apparent recombination with dif-like sequences suggests that Bacteroidetes-associated microviruses are likely to rely on the cellular chromosome dimer resolution machinery. Phylogenetic analysis of the putative major capsid proteins places the identified proviruses into a group separate from the previously characterized microviruses and gokushoviruses, suggesting that the genetic diversity and host range of bacteriophages in the family Microviridae is wider than currently appreciated.
微病毒科包含具有圆形单链 DNA 基因组的二十面体裂解病毒。该科根据基因组特征和病毒粒子结构分为两个不同的组。感染肠杆菌的病毒属于微病毒属，而感染专性寄生细菌（如衣原体、螺原体和蛭弧菌）的病毒则被分类为一个亚科，即 Gokushovirinae。最近的宏基因组研究表明，微病毒科的成员可能在海洋环境中也发挥着重要作用。在本研究中，我们鉴定并描述了以前未知与微病毒相关的前噬菌体整合在拟杆菌门物种基因组中的情况，拟杆菌门是一个以前不与微病毒相关的门。对宏基因组数据库的搜索揭示了在人类肠道中存在高度相似的序列。这是第一个表明微病毒科的病毒能使宿主发生溶原的报告。缺少相关整合酶编码基因和与 dif 样序列的明显重组表明，与拟杆菌相关的微病毒可能依赖于细胞染色体二聚体分辨率机制。假定的主要衣壳蛋白的系统发育分析将鉴定的前病毒置于与以前描述的微病毒和 gokushoviruses 不同的组中，表明微病毒科噬菌体的遗传多样性和宿主范围比目前所认识的要广泛。
