Viruses encode tRNA and anti-retron to evade bacterial immunity
Viruses encode tRNA and anti-retron to evade bacterial immunity
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病毒编码 tRNA 和抗逆转录酶以逃避细菌免疫
DOI：
10.1101/2023.03.15.532788
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Kiga Kotaro
中科院分区：
文献类型：
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作者：
Azam Aa Haeruman;Chihara Kotaro;Kondo Kohei;Nakamura Tomohiro;Ojima Shinjiro;Tamura Azumi;Yamashita Wakana;Cui Longzhu;Takahashi Yoshimasa;Watashi Koichi;Kiga Kotaro
逆转录子是细菌的遗传逆转录元件，其编码能够产生多拷贝单链DNA（msDNA）的逆转录酶，并作为抗噬菌体防御系统起作用。噬菌体使用几种策略来对抗宿主防御系统，但没有已知的逃避逆转子的机制。在这里，我们发现T5噬菌体家族的tRNATyrand Rad（retron anti-defense）分别抑制retron 78和广泛的retron的防御活性。retron 78的效应蛋白ptuAB特异性降解tRNATyr，导致感染失败，但噬菌体通过提供tRNATyr来抵消这种防御。Rad通过降解msDNA的前体非编码RNA来抑制retron功能。总之，我们证明了病毒编码至少两种独立的策略来克服细菌防御系统：抗防御，如Rad，和防御取消者，如tRNA。
Retrons are bacterial genetic retroelements that encode reverse transcriptase capable of producing multicopy single-stranded DNA (msDNA) and function as antiphage defense systems. Phages employ several strategies to counter the host defense systems, but no mechanisms for evading retrons are known. Here, we show that tRNATyrand Rad (retron anti-defense) of T5 phage family inhibit the defense activity of retron 78 and a broad range of retrons, respectively. The effector protein of retron 78, ptuAB, specifically degraded tRNATyrleading abortive infection, but phage countervailed this defense by supplying tRNATyr. Rad inhibited retron function by degrading noncoding RNA, the precursor of msDNA. In summary, we demonstrated that viruses encode at least two independent strategies for overcoming bacterial defense systems: anti-defense, such as Rad, and defense canceler, like tRNA.