The primary immunity determinant in modulating the lysogenic immunity of the filamentous bacteriophage cf
The primary immunity determinant in modulating the lysogenic immunity of the filamentous bacteriophage cf
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DOI：
10.1006/jmbi.1999.2651
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发表时间：
1999-04-16
影响因子：
5.6
通讯作者：
Kuo, TT
中科院分区：
文献类型：
--
作者：
Cheng, CM;Wang, HJ;Kuo, TT
噬菌体cf是第一个单链DNA噬菌体，已被证明建立一个稳定的溶原性状态，其基因组整合到宿主染色体。从一个强毒突变体cf-tv 2的分离和鉴定，我们报告了丝状噬菌体建立免疫机制的第一次调查。cf-tv 2中的突变使噬菌体能够在cf溶源性细胞的菌苔上产生噬斑。该突变被定义为位于cf复制型DNA的0.59 kb NcoI/KpnI片段中的49个核苷酸缺失。检测到从野生型cf的免疫区转录但方向相反的两个信息，cM 1和cM 2。在cf-tv 2中，49个核苷酸的缺失消除了cM 2的转录。引物延伸试验表明，可能存在由cM 1和cM 2 RNA的碱基配对指导的RNA-RNA相互作用。由cM 2编码的开放阅读框ORF 165的移码突变导致cf溶原细胞上的10（5）平板接种效率。这些观察结果表明，RNA-RNA相互作用和阻遏蛋白抑制参与cf免疫机制。提出了一种调节cf免疫力的模型。(C)北京：科学出版社.
Bacteriophage cf is the first single-stranded DNA phage that has been shown to set up a stable lysogenic state with its genome integrated into the host chromosome. From the isolation and characterization of a virulent mutant, cf-tv2, we report the first investigation into the mechanisms of the immunity established by the filamentous bacteriophage. The mutation in cf-tv2 enables the phage to produce plaques on lawns of cf lysogenic cells. The mutation was defined as a 49-nucleotide deletion located in a 0.59 kb NcoI/KpnI fragment of cf replicative form DNA. Two messages, cM1 and cM2, transcribed from the immunity region of wildtype cf but in opposite directions, were detected. In cf-tv2, the 49-nucleotide deletion abolishes cM2 transcription. The primer extension assay suggests a possible RNA-RNA interaction directed by base-pairing of the cM1 and cM2 RNAs. A frameshift mutation of the open reading frame ORF 165, encoded by cM2, resulted in a 10(5) plating efficiency on the cf lysogen. These observations suggest that both RNA-RNA interaction and repressor protein inhibition are involved in the mechanism of cf immunity. A model is proposed for the regulation of cf immunity. (C) 1999 Academic Press.