病毒卫星利用噬菌体蛋白逃避细菌宿主染色体的降解。
Viral Satellites Exploit Phage Proteins to Escape Degradation of the Bacterial Host Chromosome.
机构信息
Department of Plant and Microbial Biology, University of California, Berkeley, 271 Koshland Hall, Berkeley, CA 94720, USA.
ICDDR,B, formerly known as International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.
出版信息
Cell Host Microbe. 2019 Oct 9;26(4):504-514.e4. doi: 10.1016/j.chom.2019.09.006.
Phage defense systems are often found on mobile genetic elements (MGEs), where they constitutively defend against invaders or are induced to respond to new assaults. Phage satellites, one type of MGE, are induced during phage infection to promote their own transmission, reducing phage production and protecting their hosts in the process. One such satellite in Vibrio cholerae, phage-inducible chromosomal island-like element (PLE), sabotages the lytic phage ICP1, which triggers PLE excision from the bacterial chromosome, replication, and transduction to neighboring cells. Analysis of patient stool samples from different geographic regions revealed that ICP1 has evolved to possess one of two syntenic loci encoding an SF1B-type helicase, either of which PLE exploits to drive replication. Further, loss of PLE mobilization limits anti-phage activity because of phage-mediated degradation of the bacterial genome. Our work provides insight into the unique challenges facing parasites of lytic phages and underscores the adaptions of satellites to their ever-evolving target phage.
噬菌体防御系统通常存在于移动遗传元件（MGE）上，在这些元件中，它们可以持续防御入侵者，或者被诱导对新的攻击做出反应。噬菌体卫星是 MGE 的一种类型，在噬菌体感染期间被诱导，以促进自身的传播，从而减少噬菌体的产生并在这个过程中保护它们的宿主。霍乱弧菌中的一种噬菌体卫星，即噬菌体诱导的染色体岛样元件（PLE），破坏裂解噬菌体 ICP1，从而触发 PLE 从细菌染色体上的切除、复制和转导到邻近细胞。对来自不同地理区域的患者粪便样本的分析表明，ICP1 已经进化到拥有两个编码 SF1B 型解旋酶的同线性基因座之一，PLE 利用这两个基因座中的任何一个来驱动复制。此外，由于噬菌体介导的细菌基因组降解，PLE 移动性的丧失限制了抗噬菌体活性。我们的工作深入了解了裂解噬菌体寄生虫所面临的独特挑战，并强调了卫星对其不断进化的靶噬菌体的适应。
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