The virus Hardycor1 was isolated in 1998 and infects the haloarchaeon Halorubrum coriense. DNA from a frozen stock (HC1) was sequenced and the viral genome found to be 45,142 bp of dsDNA, probably having redundant, circularly permuted termini. The genome showed little similarity (BLASTn) to known viruses. Only twenty-two of the 53 (41%) predicted proteins were significantly similar to sequences in the NCBI nr protein database (E-value ≤ 10⁻¹⁵). Six caudovirus-like proteins were encoded, including large subunit terminase (TerL), major capsid protein (Mcp) and tape measure protein (Tmp). Hardycor1 was predicted to be a siphovirus (VIRFAM). No close relationship to other viruses was found using phylogenetic tree reconstructions based on TerL and Mcp. Unexpectedly, the sequenced virus stock HC1 also revealed two induced proviruses of the host: a siphovirus (Humcor1) and a pleolipovirus (Humcor2). A re-examination of other similarly sequenced, archival virus stocks revealed induced proviruses of Haloferax volcanii, Haloferax gibbonsii and Haloarcula hispanica, three of which were pleolipoviruses. One provirus (Halfvol2) of Hfx. volcanii showed little similarity (BLASTn) to known viruses and probably represents a novel virus group. The attP sequences of many pleolipoproviruses were found to be embedded in a newly detected coding sequence, split in the provirus state, that spans between genes for integrase and a downstream CxxC-motif protein. This gene might play an important role in regulation of the temperate state.

中文翻译：

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新型晕病毒Hardycor1，和四个卤古菌中活跃的（诱导）原病毒的存在

1998年分离出Hardycor1病毒，并感染了晕链杆菌Halorubrum coriense。对来自冷冻原种（HC1）的DNA进行测序，发现病毒基因组为dsDNA的45,142 bp，可能具有多余的，圆形排列的末端。基因组与已知病毒几乎没有相似性（BLASTn）。53种预测蛋白质中只有22种（41％）与NCBI nr蛋白质数据库中的序列非常相似（E值≤10 ^-15）。编码了六种类似于caudovirus的蛋白，包括大亚基末端酶（TerL），主要衣壳蛋白（Mcp）和卷尺蛋白（Tmp）。Hardycor1被认为是siphovirus（VIRFAM）。使用基于TerL和Mcp的系统树重建，未发现与其他病毒有密切关系。出乎意料的是，测序的病毒原液HC1还显示出宿主的两种诱导型原病毒：siphovirus（Humcor1）和pleolipovirus（Humcor2）。重新检查其他类似序列的档案病毒原种后，发现了诱导的原发性Haloferax volcanii，Haloferax gibbonsii和Halolarcula hispanica的原病毒，其中三种是胸膜脂病毒。Hfx的一种前病毒（Halfvol2）。火山与已知病毒几乎没有相似之处（BLASTn），可能代表一个新病毒组。发现许多胸膜脂原病毒的attP序列被嵌入到新检测到的编码序列中，该序列在前病毒状态下分裂，该序列介于整合基因和下游CxxC-基序蛋白之间。该基因可能在调节温带状态中起重要作用。