Louarn J M, Bird R E
Proc Natl Acad Sci U S A. 1974 Feb;71(2):329-33. doi: 10.1073/pnas.71.2.329.
Newly synthesized DNA, in E. coli lysogenic for the phage lambda, was labeled by short pulses of [(3)H]-thymidine, isolated, and separated on the basis of size by alkaline sucrose density gradient centrifugation. The molecular polarity of this DNA was determined by hybridization with each of the separated strands of lambda DNA. The results show that, in the 3' to 5' direction, replication proceeds by synthesis of short chains that are subsequently joined to long DNA. This is true for both a polA(+) and a polA(-) strain. (The polA locus codes for DNA polymerase I.) In the 5' to 3' direction, replication proceeds continuously, by addition of nucleotides to long DNA, for the polA(+) strain. In the polA(-) strain, however, replication in the 5' to 3' direction is also discontinuous, but the discontinuities are 1-40 times less frequent than in the other direction.
在噬菌体λ溶原性的大肠杆菌中，新合成的DNA通过短脉冲的[³H] - 胸腺嘧啶进行标记，分离后，通过碱性蔗糖密度梯度离心根据大小进行分离。这种DNA的分子极性通过与λDNA的每条分离链杂交来确定。结果表明，在3'至5'方向上，复制通过合成短链进行，这些短链随后连接成长DNA。对于polA(+)和polA(-)菌株都是如此。（polA基因座编码DNA聚合酶I。）在5'至3'方向上，polA(+)菌株通过向长DNA添加核苷酸连续进行复制。然而，在polA(-)菌株中，5'至3'方向上的复制也是不连续的，但不连续性比另一个方向少1 - 40倍。
