La Trobe Institute for Molecular Sciences, La Trobe University, Victoria 3552, Australia.
J Virol. 2012 Jan;86(1):358-63. doi: 10.1128/JVI.05460-11. Epub 2011 Oct 19.
Bacteriophages are considered to be the most abundant biological entities on the planet. The Siphoviridae are the most commonly encountered tailed phages and contain double-stranded DNA with an average genome size of ∼50 kb. This paper describes the isolation from four different activated sludge plants of the phage RRH1, which is polyvalent, lysing five Rhodococcus species. It has a capsid diameter of only ∼43 nm. Whole-genome sequencing of RRH1 revealed a novel circularly permuted DNA sequence (14,270 bp) carrying 20 putative open reading frames. The genome has a modular arrangement, as reported for those of most Siphoviridae phages, but appears to encode only structural proteins and carry a single lysis gene. All genes are transcribed in the same direction. RRH1 has the smallest genome yet of any described functional Siphoviridae phage. We demonstrate that lytic phage can be recovered from transforming naked DNA into its host bacterium, thus making it a potentially useful model for studying gene function in phages.
噬菌体被认为是地球上最丰富的生物实体。长尾噬菌体科是最常见的有尾噬菌体，含有平均大小为 50kb 的双链 DNA。本文描述了从四个不同的活性污泥厂分离出多价噬菌体 RRH1 的情况，该噬菌体可以裂解五种罗奇氏菌。它的衣壳直径只有约 43nm。RRH1 的全基因组测序揭示了一种新型的环状排列的 DNA 序列（14270bp），带有 20 个可能的开放阅读框。该基因组具有模块化排列，与大多数长尾噬菌体科噬菌体的报告一致，但似乎只编码结构蛋白，并且携带单个裂解基因。所有基因都按相同的方向转录。RRH1 是迄今为止描述的功能最齐全的 Siphoviridae 噬菌体中基因组最小的。我们证明，裂解噬菌体可以从转化的裸露 DNA 中回收，从而使其成为研究噬菌体中基因功能的潜在有用模型。
