Anti-Clustered regularly interspaced small palindromic repeat (CRISPR) (Acr) phages cooperate to establish a successful infection in CRISPR-containing host. We report here the selective advantage provided by a replication initiator, Rep, toward cooperative host immunosuppression by viruses encoding Acrs. A rep knockout mutant (Δgp16) of Sulfolobus islandicus rod-shaped virus 2 produced around fourfold less virus in a CRISPR-null host, suggesting that Rep is the major replication initiator. In addition to Rep-dependent replication initiation from the viral genomic termini, we detected Rep-independent replication initiation from nonterminal sites. Intriguingly, despite the presence of Acrs, lack of Rep showed a profound effect on virus propagation in a host carrying CRISPR-Cas immunity. Accordingly, the co-infecting parental virus (rep-containing) outcompeted the Δgp16 mutant much more quickly in the CRISPR-containing host than in CRISPR-null host. Despite the nonessentiality, rep is carried by all known members of Rudiviridae, which is likely an evolutionary outcome driven by the ubiquitous presence of CRISPR-Cas in Sulfolobales.

中文翻译：

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复制蛋白 Rep 在存在 CRISPR-Cas 免疫力的情况下为病毒提供选择性优势

抗成簇规则间隔小回文重复序列 (CRISPR) (Acr) 噬菌体协同在含有 CRISPR 的宿主中建立成功感染。我们在这里报告复制启动器 Rep 提供的选择性优势，通过编码 Acrs 的病毒对合作宿主免疫抑制。Sulfolobus islandicus的rep敲除突变体(Δ gp16 )杆状病毒 2 在 CRISPR 无效宿主中产生的病毒少了大约四倍，表明 Rep 是主要的复制启动子。除了来自病毒基因组末端的 Rep 依赖性复制启动外，我们还检测到来自非末端位点的 Rep 独立复制启动。有趣的是，尽管存在 Acrs，但 Rep 的缺乏对病毒在携带 CRISPR-Cas 免疫力的宿主中的传播产生了深远的影响。因此，与在 CRISPR 无效宿主中相比，在含有 CRISPR 的宿主中，共感染的亲代病毒（含有rep）在竞争中更快地击败了 Δ gp16突变体。尽管不重要，代表由 Rudiviridae 的所有已知成员携带，这可能是由 CRISPR-Cas 在硫化叶菌目中普遍存在所驱动的进化结果。