2 DNA ANTIRESTRICTION SYSTEMS OF BACTERIOPHAGE-P1, DARA, AND DARB - CHARACTERIZATION OF DARA PHAGES
2 DNA ANTIRESTRICTION SYSTEMS OF BACTERIOPHAGE-P1, DARA, AND DARB - CHARACTERIZATION OF DARA PHAGES
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DOI：
10.1016/0042-6822(87)90324-2
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发表时间：
1987-03-01
期刊：
影响因子：
3.7
通讯作者：
ARBER, W
中科院分区：
文献类型：
--
作者：
IIDA, S;STREIFF, MB;ARBER, W
噬菌体P1仅在感染携带I型限制和修饰系统的细胞时受到弱限制，即使从P1噬菌体颗粒纯化的DNA是I型限制酶体外的良好底物。在这里，我们表明，这种对限制的保护是由于两个噬菌体基因的产物，我们称之为达拉和darB（dar为防御限制）。每种dar基因产物提供针对I型限制系统的不同子集的保护。 在噬菌体头部发现了达拉和darB基因产物，并保护包装到噬菌体头部的任何DNA，包括转导的染色体标记，免受限制。因此，蛋白质必须与DNA一起沿着注入受体细胞。蛋白质严格按顺式作用。例如，在用dar+和dar-P1 β双重感染限制性细胞时，dar+基因组被保护免于限制，而dar-基因组被有效地限制。
Bacteriophage P1 is only weakly restricted when it infects cells carrying type I restriction and modification systems even though DNA purified from P1 phage particles is a good substrate for type I restriction enzymes in vitro. Here we show that this protection against restriction is due to the products of two phage genes which we call darA and darB (dar for defense against restriction). Each of the dar gene products provides protection against a different subset of type I restriction systems. The darA and darB gene products are found in the phage head and protect any DNA packaged into a phage head, including transduced chromosomal markers, from restriction. The proteins must, therefore, be injected into recipient cells along with the DNA. The proteins act strictly in cis. For example, upon double infection of restricting cells with dar+ and dar- P1 phages, the dar+ genomes are protected from restriction while the dar- genomes are efficiently restricted.