MUTANTS OF BACTERIOPHAGE-T4 WHICH ALLOW AMBER MUTANTS OF GENE-32 TO GROW IN OCHRE-SUPPRESSING HOSTS
MUTANTS OF BACTERIOPHAGE-T4 WHICH ALLOW AMBER MUTANTS OF GENE-32 TO GROW IN OCHRE-SUPPRESSING HOSTS
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DOI：
10.1016/0042-6822(73)90464-9
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发表时间：
1973-01-01
期刊：
影响因子：
3.7
通讯作者：
LITTLE, JW
中科院分区：
文献类型：
--
作者：
LITTLE, JW
噬菌体T4基因32的产物，DNA解旋蛋白或32蛋白，是正常噬菌体生长所需的大量蛋白。基因32琥珀突变体不能在赭石抑制宿主上形成噬斑，可能是因为32蛋白太少而无法有效生长。然而，出现的变体可以在这些宿主上形成小的浑浊斑块。这些变异体包含第二个突变，termedsud，它位于基因39和56之间，远离基因32。Sud突变体对野生型是隐性的。就其本身而言，突变体相对于野生型在快速DNA合成的开始方面表现出短暂的延迟。A453（基因32）-suddouble突变体在感染赭石抑制宿主时，相对于野生型表现出非常长的DNA合成延迟，之后DNA合成以与野生型相同的速率进行，而A453在短延迟后以野生型所示的30%的速率合成DNA。此外，amA 453将DNA转化为成熟后代的效率比野生型低得多，而所描述的突变体之一在这方面更接近野生型。这些意见的可能意义进行了讨论。
The product of bacteriophage T4 gene 32, DNA-unwinding protein or 32 protein, is required in large amounts for normal phage growth. Gene 32 amber mutants are unable to form plaques on ochre-suppressing hosts, presumably because there is too little 32 protein for efficient growth. However, variants arise which can form small, turbid plaques on these hosts. These variants contain a second mutation, termedsud, which maps between genes 39 and 56, far from gene 32.Sudmutants are recessive to wildtype. By themselves,sudmutants exhibit a short delay in the onset of rapid DNA synthesis relative to wild-type. TheamA453 (gene 32)-suddouble mutants exhibit a very long delay in DNA synthesis relative to wild-type when infecting the ochre-suppressing host, after which DNA synthesis proceeds at the same rate as shown by wild-type, whileamA453 synthesizes DNA at a rate 30% that shown by wild-type after a short delay. Moreover,amA453 converts the DNA made to mature progeny much less efficiently than does wild-type, whereas one of thesudmutants described resembles wild-type more closely in this respect. The possible meaning of these observations is discussed.