Unravelling the Role of the F55 Regulator in the Transition from Lysogeny to UV Induction of Sulfolobus Spindle-Shaped Virus 1
Unravelling the Role of the F55 Regulator in the Transition from Lysogeny to UV Induction of Sulfolobus Spindle-Shaped Virus 1
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DOI：
10.1128/jvi.00363-15
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发表时间：
2015-06-01
影响因子：
5.4
通讯作者：
Contursi, Patrizia
中科院分区：
文献类型：
--
作者：
Fusco, Salvatore;She, Qunxin;Contursi, Patrizia
硫化叶菌梭形病毒1代表了在恶劣环境中研究病毒-宿主相互作用的模型，并且它是迄今为止唯一显示UV诱导生命周期的梭形病毒科成员。虽然该病毒已被广泛研究，但维持溶原性的机制以及调节UV诱导的机制很少受到关注。最近，一个新的SSV 1转录因子，F55，被确定。该因子能够在体外与来自SSV 1基因组的早期和UV诱导型启动子的几个序列结合。这些结合位点的位置以及F55对这些序列的不同亲和力导致了这样的假设，即该蛋白可能参与了SSV 1溶原性的维持。在这里，我们报告的分子事件发生在紫外线诱导区域的SSV 1基因组的体内调查，重点是F55的结合曲线之前和之后的紫外线照射。F55与靶启动子的结合与转录抑制相关，而其解离则由转录激活所抑制。因此，我们建议F55作为一个分子开关的转录调控的早期病毒基因。
Sulfolobus spindle-shaped virus 1 represents a model for studying virus-host interaction in harsh environments, and it is so far the only member of the family Fuselloviridae that shows a UV-inducible life cycle. Although the virus has been extensively studied, mechanisms underpinning the maintenance of lysogeny as well as those regulating the UV induction have received little attention. Recently, a novel SSV1 transcription factor, F55, was identified. This factor was able to bind in vitro to several sequences derived from the early and UV-inducible promoters of the SSV1 genome. The location of these binding sites together with the differential affinity of F55 for these sequences led to the hypothesis that this protein might be involved in the maintenance of the SSV1 lysogeny. Here, we report an in vivo survey of the molecular events occurring at the UV-inducible region of the SSV1 genome, with a focus on the binding profile of F55 before and after the UV irradiation. The binding of F55 to the target promoters correlates with transcription repression, whereas its dissociation is paralleled by transcription activation. Therefore, we propose that F55 acts as a molecular switch for the transcriptional regulation of the early viral genes.