Erez Zohar, Steinberger-Levy Ida, Shamir Maya, Doron Shany, Stokar-Avihail Avigail, Peleg Yoav, Melamed Sarah, Leavitt Azita, Savidor Alon, Albeck Shira, Amitai Gil, Sorek Rotem
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel.
Nature. 2017 Jan 26;541(7638):488-493. doi: 10.1038/nature21049. Epub 2017 Jan 18.
Temperate viruses can become dormant in their host cells, a process called lysogeny. In every infection, such viruses decide between the lytic and the lysogenic cycles, that is, whether to replicate and lyse their host or to lysogenize and keep the host viable. Here we show that viruses (phages) of the SPbeta group use a small-molecule communication system to coordinate lysis-lysogeny decisions. During infection of its Bacillus host cell, the phage produces a six amino-acids-long communication peptide that is released into the medium. In subsequent infections, progeny phages measure the concentration of this peptide and lysogenize if the concentration is sufficiently high. We found that different phages encode different versions of the communication peptide, demonstrating a phage-specific peptide communication code for lysogeny decisions. We term this communication system the 'arbitrium' system, and further show that it is encoded by three phage genes: aimP, which produces the peptide; aimR, the intracellular peptide receptor; and aimX, a negative regulator of lysogeny. The arbitrium system enables a descendant phage to 'communicate' with its predecessors, that is, to estimate the amount of recent previous infections and hence decide whether to employ the lytic or lysogenic cycle.
温和噬菌体可在其宿主细胞中进入休眠状态，这一过程称为溶原化。在每次感染中，此类噬菌体要在裂解周期和溶原周期之间做出选择，即决定是复制并裂解宿主，还是进入溶原状态并使宿主存活。我们在此表明，SPbeta组噬菌体利用一种小分子通讯系统来协调裂解-溶原决定。在感染其芽孢杆菌宿主细胞期间，噬菌体产生一种由六个氨基酸组成的通讯肽，并释放到培养基中。在随后的感染中，子代噬菌体测量这种肽的浓度，如果浓度足够高就进入溶原状态。我们发现不同的噬菌体编码不同版本的通讯肽，这表明存在一种用于溶原决定的噬菌体特异性肽通讯密码。我们将这种通讯系统称为“仲裁”系统，并进一步表明它由三个噬菌体基因编码：产生肽的aimP、细胞内肽受体aimR以及溶原的负调节因子aimX。“仲裁”系统使子代噬菌体能够与其前辈“通讯”，即估计近期先前感染的数量，从而决定采用裂解周期还是溶原周期。
