Identification of a potential new sub family of DNA polymerase in bacteriophages.

Bacteriophages (bacterial viruses) are the most abundant organisms on earth. In order to replicate, bacteriophages hijack and eventually kill bacteria, making them a potential useful tool to treat bacterial infection. They contain the biggest diversity of modified nucleobases observed in nature so far, that prevent them from cleavage by host restriction endonucleases. However, this modified alphabet of nucleobases can make the genome of such bacteriophages resistant to sequencing by commercial polymerases. The discovery of a polymerase capable of reading any type of modified genomic DNA would be a great tool for the knowledge of this hidden viral world. Recently, the bacteriophage YERA41, that infects Yersinia ruckeri bacteria, was isolated. It appears to be an unconventional phage that contains hypermodified thymidine in its genomic DNA, that only the phage DNA polymerase (DNAP) can replicate.

噬菌体（Bacteriophages，一类细菌病毒）是地球上丰度最高的生物体。为完成复制周期，噬菌体会劫持宿主细菌并最终将其裂解，这使其成为治疗细菌感染的潜在有效工具。这类噬菌体拥有自然界迄今已报道的种类最多的修饰核苷碱基，这类修饰可避免其基因组被宿主限制性内切酶切割。然而，这类经修饰的核苷碱基组会赋予此类噬菌体基因组以商用聚合酶测序抗性。若能开发出可读取任意类型修饰化基因组DNA的聚合酶，将为探究这一隐秘的病毒世界提供关键研究工具。近期，研究人员分离出了一株可侵染鲁氏耶尔森菌（Yersinia ruckeri）的噬菌体YERA41。该噬菌体属于非常规噬菌体，其基因组DNA中含有高度修饰的胸苷，这类修饰仅能被该噬菌体自身的DNA聚合酶（DNAP）完成复制。