Non-CRISPR phage survival in Streptococcus thermophilus DGCC7710

Streptococcus thermophilus is a model organism for the study of CRISPR-Cas immunity against lytic phages. In addition to CRISPR-Cas, this organism has other mechanisms to survive or evade phage infection. In this study we identified ftsH, a gene encoding a cell wall anchored ATP-dependent protease, as an important regulator of phage attachment. Mutations in ftsH protected against phage infection. In turn, mutations in phage tail proteins allowed them to re-establish infection.

嗜热链球菌（Streptococcus thermophilus）是研究针对裂解性噬菌体（lytic phages）的CRISPR-Cas免疫（CRISPR-Cas immunity）机制的模式生物。除CRISPR-Cas系统外，该菌株还具备其他抵御或逃逸噬菌体感染的分子机制。本研究中，我们鉴定出ftsH基因——一种编码细胞壁锚定ATP依赖蛋白酶（ATP-dependent protease）的基因——作为噬菌体吸附（phage attachment）过程的关键调控因子。ftsH基因的突变可赋予宿主抗噬菌体感染的能力；反之，噬菌体尾部蛋白的突变则可使噬菌体重新建立感染能力。