ESCHERICHIA COLI MUTANTS WITH TEMPERATURE SENSITIVE SYNTHESIS OF DNA
ESCHERICHIA COLI MUTANTS WITH TEMPERATURE SENSITIVE SYNTHESIS OF DNA
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DOI：
10.1007/bf00269647
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发表时间：
1970-01-01
期刊：
影响因子：
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通讯作者：
CARL, PL
中科院分区：
文献类型：
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作者：
CARL, PL
7个突变株。已分离出具有温度敏感性DNA合成的大肠杆菌。RNA、蛋白质和DNA前体的合成似乎没有受到直接影响。根据它们的DNA合成模式、它们在41 °下支持噬菌体生长的能力和它们的遗传作图，这些突变体至少可分为两类：第一类突变体在40 °下的DNA合成模式是异质的。一些突变体在转移到40 °时突然停止DNA合成，几乎检测不到任何残留的DNA合成。在其他情况下，在40 °下有大量的残余合成。然而，所有这些第1组突变体都是相似的，因为它们支持噬菌体T4的生长，但在41 °下不支持λ。两个几乎检测不到残留DNA合成的突变体携带的DNA突变已被定位P1转导，并显示约72%的连锁themalBlocus。目前还不能证明能够精确地定位显示大量残留合成的突变体，也不能排除这些突变存在于不同基因中的可能性。像一些第1组突变体一样，它在合成停止前在40 °合成大量的DNA。然而，与它们不同的是，它支持T4和Lambda在41 °的生长。DNA突变图谱位于基因座附近。该突变体的某些性质与DNA合成的起始在该菌株中是温度敏感的这一想法一致。
Seven mutants ofE. coliwith temperature-sensitive synthesis of DNA have been isolated. Synthesis of RNA, protein and DNA precursors does not appear to be directly affected. The mutants can be divided into at least two groups on the basis of their pattern of DNA synthesis, their ability to support phage growth at 41° and their genetic mapping.Mutants of the first group are heterogeneous in their pattern of DNA synthesis at 40°. Some mutants cease DNA synthesis abruptly upon transfer to 40° and any residual DNA synthesis is barely detectable. In others there is substantial residual synthesis at 40°. All these Group 1 mutants are alike, however, in that they support the growth of phage T4 but not Lambda at 41°. Two mutants with barely detectable residual DNA synthesis carry DNA mutations which have been mapped by P1 transduction and show about 72% linkage to themalBlocus. It has not yet proved possible to map accurately the mutants showing substantial residual synthesis, and the possibility that these mutations are in a different gene(s) has not been excluded.A single mutant has been placed in a second group. Like some Group 1 mutants it synthesizes substantial amounts of DNA at 40° before synthesis stops. However, unlike them it supports the growth of T4andLambda at 41°. The DNA mutation maps near theleulocus. Certain properties of this mutant are consistent with the idea that initiation of DNA synthesis is temperature-sensitive in this strain.