DNA PACKAGING BY THE BACILLUS-SUBTILIS DEFECTIVE BACTERIOPHAGE-PBSX
DNA PACKAGING BY THE BACILLUS-SUBTILIS DEFECTIVE BACTERIOPHAGE-PBSX
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DOI：
10.1128/jvi.54.3.773-780.1985
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发表时间：
1985-01-01
影响因子：
5.4
通讯作者：
BOTT, KF
中科院分区：
文献类型：
--
作者：
ANDERSON, LM;BOTT, KF
有缺陷的噬菌体PBSX，是所有B的居民。枯草芽孢杆菌168条染色体，当被丝裂霉素C诱导时，包装来自宿主染色体所有部分的DNA片段。在这项研究中，染色体和质粒DNA物种的DNA包装的物理过程进行了检查。野生型噬菌体包装离散的13-DNA酶（kb）长度的DNA，该过程是抗DNA酶I的，可能发生的头部填充机制。使用在染色体的2个不同区域具有作为遗传标记整合的氯霉素抗性决定子的遗传工程化的等基因宿主菌株来监测特定染色体区域的包装。这些区域没有明显的选择性。如果野生型菌株168含有自主复制的质粒，特别是pC 194，丝裂霉素C诱导驻留质粒DNA的大小增加，然后将其包装成13-kb片段进入噬菌体头部。在菌株RB 1144中，其缺乏PBSX驻留噬菌体区的实质性部分，丝裂霉素C处理不影响驻留质粒的结构。PBSX的诱导开始在质粒上进行滚环复制，然后将其包装成13-kb片段。丝裂霉素C处理导致的质粒复制的这种改变或同类相食需要菌株RB 1144的原噬菌体缺失内的一些DNA来实现其功能。
Defective bacteriophage PBSX, a resident of all B. subtilis 168 chromosomes, packages fragments of DNA from all portions of the host chromosome when induced by mitomycin C. In this study, the physical process for DNA packaging of both chromosomal and plasmid DNA species was examined. Discrete 13-kilobase (kb) lengths of DNA were packaged by wild-type phage, and the process was DNase I resistant and probably occurred by a head-filling mechanism. Genetically engineered isogenic host strains having a chloramphenicol resistance determinant integrated as a genetic flag at 2 different regions of the chromosome were used to monitor the packaging of specific chromosomal regions. No dramatic selectivity for these regions could be documented. If the wild-type strain 168 contains autonomously replicating plasmids, especially pC194, the mitomycin C induces an increase in size of resident plasmid DNA, which is then packaged as 13-kb pieces into phage heads. In strain RB1144, which lacks substantial portions of the PBSX resident phage region, mitomycin C treatment did not affect the structure of resident plasmids. Induction of PBSX started rolling circle replication on plasmids, which then became packaged as 13-kb fragments. This alteration or cannibalization of plasmid replication resulting from mitomycin C treatment requires for its function some DNA within the prophage deletion of strain RB1144.