Kowalski J, Denhardt D T
Nucleic Acids Res. 1978 Nov;5(11):4355-73. doi: 10.1093/nar/5.11.4355.
The population of short DNA molecules (less than 10(3) nucleotides) in 3T3 cells has been studied using in vivo and in vitro pulse labeling techniques and in vitro end-labeling. There is a large number of molecules of less than 100 nucleotides present in equal numbers in both Go and S phase cells. In S phase cells, most of these molecules are not replicating intermediates because they do not become density-labeled after a moderate period of substitution of BrdUMP, although they are detected by end-labeling in vitro. This population includes the nascent Okazaki pieces that can be labeled in a short pulse with [3H]dThd or [3H]dTTP, however, these represent less than 10% of the total population. Alkaline hydrolysis of the molecules that had been end-labeled with 32P using [gamma32P]ATP and polynucleotide kinase did not reveal significant release of [32P] 2'(3'), 5' ribonucleoside diphosphates.
利用体内和体外脉冲标记技术以及体外末端标记法，对3T3细胞中短DNA分子（少于10³个核苷酸）的群体进行了研究。在G₀期和S期细胞中，存在大量少于100个核苷酸的分子，且数量相等。在S期细胞中，这些分子中的大多数并非复制中间体，因为在适度替换BrdUMP一段时间后，它们并未被密度标记，尽管在体外末端标记中可检测到它们。这个群体包括能用[³H]dThd或[³H]dTTP进行短脉冲标记的新生冈崎片段，然而，这些片段占总群体的比例不到10%。使用[γ³²P]ATP和多核苷酸激酶对用³²P进行末端标记的分子进行碱性水解，未发现[³²P] 2'(3'), 5'核糖核苷二磷酸有显著释放。
