Taylor J H
Proc Natl Acad Sci U S A. 1973 Apr;70(4):1083-7. doi: 10.1073/pnas.70.4.1083.
From Chinese hamster cells, blocked at the beginning of the S phase by treatment with fluorodeoxyuridine and pulse-labeled with [(3)H]thymidine, one can release segments of native DNA containing template polyuncleotide chains and the most recently replicated DNA. The segments, which can be released without shear by lysis at temperatures below the melting point for the double helix, can be separated from both the nascent single chains (Okazaki pieces) and the long strands of native DNA in sodium perchlorate gradients. These 26S segments are equivalent to about 6 mum of native DNA, but may be replication forks rather than linear pieces.
用氟脱氧尿苷处理中国仓鼠细胞,使其在S期开始时被阻断,并用[³H]胸腺嘧啶核苷进行脉冲标记,这样就能释放出包含模板多核苷酸链和最新复制DNA的天然DNA片段。这些片段在低于双螺旋熔点的温度下通过裂解即可无剪切地释放出来,在高氯酸钠梯度中可与新生单链(冈崎片段)和天然DNA长链分离。这些26S片段相当于约6μm的天然DNA,但可能是复制叉而非线性片段。