Sulfolobus spindle-shaped virus 1 is the only UV-inducible member of the virus family Fuselloviridae. Originally isolated from Saccharolobus shibatae B12, it can also infect Saccharolobus solfataricus. Like the CI repressor of the bacteriophage λ, the SSV1-encoded F55 transcription repressor acts as a key regulator for the maintenance of the SSV1 carrier state. In particular, F55 binds to tandem repeat sequences located within the promoters of the early and UV-inducible transcripts. Upon exposure to UV light, a temporally coordinated pattern of gene expression is triggered. In the case of the better characterized bacteriophage λ, the switch from lysogenic to lytic development is regulated by a crosstalk between the virus encoded CI repressor and the host RecA, which regulates also the SOS response. For SSV1, instead, the regulatory mechanisms governing the switch from the carrier to the induced state have not been completely unravelled. In this study we have applied an integrated biochemical approach based on a variant of the EMSA assay coupled to mass spectrometry analyses to identify the proteins associated with F55 when bound to its specific DNA promoter sequences. Among the putative F55 interactors, we identified RadA and showed that the archaeal molecular components F55 and RadA are functional homologs of bacteriophage λ (factor CI) and Escherichia coli (RecA) system.

中文翻译：

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F55病毒编码的转录调节因子与RadA宿主重组酶之间的相互作用揭示了古细菌和细菌中的一种常见策略，即可以检测UV诱导的宿主DNA损伤。

硫杆菌梭形病毒1是Fuselloviridae病毒家族中唯一可被紫外线诱导的成员。最初从Saccharolobus shibatae B12分离，它也可以感染Saccharolobus solfataricus。像噬菌体λ的CI阻遏物一样，SSV1编码的F55转录阻遏物充当维持SSV1载体状态的关键调节剂。特别地，F55与位于早期和紫外线诱导的转录本的启动子内的串联重复序列结合。一旦暴露于紫外线下，就会触发基因表达的时间协调模式。在具有更好特征的噬菌体λ的情况下，从溶原性到裂解性发展的转变是由病毒编码的CI阻遏物与宿主RecA之间的串扰来调节的，该串扰还调节SOS反应。对于SSV1，控制从载体到诱导状态的转换的调节机制尚未完全阐明。在这项研究中，我们基于EMSA分析的一种变体与质谱分析结合使用了一种综合生化方法，以鉴定与F55特异性DNA启动子序列结合的蛋白质。在推定的F55相互作用体中，我们鉴定了RadA，并表明古细菌分子组分F55和RadA是噬菌体λ（因子CI）和大肠杆菌（RecA）系统的功能同源物。在这项研究中，我们基于EMSA分析的一种变体与质谱分析结合使用了一种综合生化方法，以鉴定与F55特异性DNA启动子序列结合的蛋白质。在推定的F55相互作用体中，我们鉴定了RadA，并表明古细菌分子组分F55和RadA是噬菌体λ（因子CI）和大肠杆菌（RecA）系统的功能同源物。在这项研究中，我们基于EMSA分析的一种变体与质谱分析相结合，采用了一种综合的生化方法，以鉴定与F55结合的特定DNA启动子序列相关的蛋白质。在推定的F55相互作用体中，我们鉴定了RadA，并表明古细菌分子组分F55和RadA是噬菌体λ（因子CI）和大肠杆菌（RecA）系统的功能同源物。