title: Most short DNA molecules isolated from 3T3 cells are not nascent.
abstract: 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.
mesh_terms: D002460:Cell Line; D004247:DNA / Q000096:biosynthesis / Q000302:isolation & purification; D007553:Isotope Labeling; D008970:Molecular Weight; D014316:Tritium
chemical_list: D014316:Tritium; D004247:DNA