Intermediate fragments of the newly replicated DNA in mammalian cells

Discontinuous DNA Synthesis in Mammalian Cells

“…Such evidence has been obtained both in in vivo studies (Painter & Schaefer, 1969;Schandl & Taylor, 1969;Baker, 1971;Cheevers et aL, 1972;Fareed & Salzman, 1972;Laipis & Levine, 1973;Magnusson, 1973a;Berger & Huang, 1974;Qasba, 1974b;Gautschi & Clarkson, 1975;Mendelsohn et al, 1975;Tseng & Goulian, 1975a;Vlak et al, 1975) and in more rigorous in vitro experiments (Kidwell & Mueller, 1969;Mueller, 1969;Magnusson, 1973;Magnusson et aL, 1973;Francke & Hunter, 1974a, b;Qasba, 1974a;Hunter & Francke, 1975;Otto & Reichard, 1975;Tseng & Goulian, 1975a;Fraser, unpublished sedimenting at a position between the Okazaki and bulk peaks (Painter, 1968;Taylor & Miner, 1968;Habener et al, 1969b;Kidwell & Mueller, 1969;Mueller, 1969;Schandl & Taylor, 1969;Berger & Irvin, 1970;Hyodo et al, 1970Hyodo et al, , 1971Chiu & Rauth, 1972, Gautschi 8t al., 1973Goldstein & Rutman, 1973;Berger & Huang, 1974;Kohn et al, 1974;Friedman et al, 1975;Rajalakshmi & Sarma, 1975;Sak...…”

“…When I first started this project, there were several researchers who did not find Okazaki fragments in higher organisms (Tsukada et al , 1968;Lehmann & Ormerod, 1969Habener et al, 1969b;Berger & Irvin, 1970;Hyodo et al, 1970;M. S. Horwitz, 1971).…”

Differences in timing of replication and maturation of nascent DNA fragments between satellite and main band DNA during the S phase of the first cell cycle in cultured carrot root explants.

“…In isolated HeLa cell nuclei, a shift of labeled 5-6S DNA to 8-lOS components was reported (Friedman, 1974). Accumulation of 60-1005 intermediates was also reported in cultured mouse cells (Hyodo et al, 1971). Later Rawles and Collins (1977) observed very rapid conversion of 4.5S DNA to 11S and 50-60S components, and gradual conversion of the 50-60S components to two distinct size classes, 2125 and 2755, in human fibroblast cells.…”

The use of agarose gel electrophoresis to measure the size of DNA molecules in crude cell lysates

“…This presents a fundamental problem,: no known DNA polymeras'e can synthesize 'in the 3 '---1 5' direction 1. (Hyodo et al, 1970;Berger and l rvin, 1970). …”

“…give rise ta high malecular weight DNA (Kidwell and Mueller, 1969;Hyodo et al, 1970 '--",,1973a and1973b;Pigiet et al, 1973;Salpnan and Tharen, 1973 seconds at 25°C. After this, the peak of radioàctive profiles is shifted to higher sedimentation values.…”