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Analysis of the mechanism of cell lysis by RNA phage SP

RNA噬菌体SP裂解细胞的机制分析

基本信息

批准号：
04680261
负责人：
INOKUCHI Yoshio
金额：
$ 1.28万
依托单位：
Teikyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04680261/
关键词：
RNA phage SP Lysis gene A2 gene PCR Antisense RNA RNAファージ溶菌蛋白質

项目摘要

A2 protein is one of the proteins which constitute the phage particle. In the case of phage *beta which is closely related to phage SP, the overproduction of the A2 protein causes the cell lysis when the A2 gene is cloned and expressed on the plasmid. In order to investigate the participation of the A2 gene of phage SP in the lysis, we constructed the clones harboring the A2 gene downstream from the lac or the cro promoter of the plasmid pUC8 or pSP857CRO, respectively. But the cells did not lyse upon induction of the A2 gene in every case, although the cell growth was suppressed in the latter case. On the other hand, when the antisense RNAs against the A2 gene were expressed during SP phage infection, the cell lysis was prevented, however, the phage assembly proceeded normaly within the cells. These results suggest that the A2 gene is responsible for the cell lysis and that phage assembly and lysis are distinct functions of the A2 protein.When we carried out PCR using RNAs prepared from the uninfected cells as templates and the oligonucleotides identical to the A2 gene as primers, we found that the distinct length of DNAs were amplified. The nucleotide sequences of these DNAs were found to be homologous to that of the A2 cDNA.We propose that there are the segments similar to the A2 gene on the host chromosome.

A2蛋白是构成噬菌体颗粒的蛋白质之一。在与噬菌体SP密切相关的噬菌体*β噬菌体中，当A2基因被克隆并在质粒上表达时，A2蛋白的过量生产导致细胞裂解。为了研究噬菌体SP的A2基因在裂解过程中的作用，我们构建了分别位于pUC8或pSP857CRO的lac和cro启动子下游的A2基因克隆。但并不是所有的细胞在A2基因诱导后都有溶解，尽管在后一种情况下细胞生长受到抑制。另一方面，当针对A2基因的反义RNA在SP噬菌体感染过程中表达时，细胞裂解被阻止，但噬菌体在细胞内的组装正常进行。这些结果表明，A2基因负责细胞裂解，噬菌体组装和裂解是A2蛋白的不同功能。当我们以未感染细胞的RNA为模板，以与A2基因相同的寡核苷酸为引物进行聚合酶链式反应时，我们发现扩增出不同长度的DNA。这些DNA的核苷酸序列与A2基因的核苷酸序列是同源的，我们推测宿主染色体上存在与A2基因相似的片段。