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  • R Hand
  • The Journal of cell biology
  • 1975
The regulation of DNA replication at a subchromosomal level in mammalian cells has been investigated. DNA fiber autoradiographs were prepared from mouse L-929 cells pulse labeled with (3H)thymidine. Initiation events and subsequent chain growth occurring over short stretches (up to three replication units in length) of chromosomal DNA were analyzed. The(More)
  • R Hand, J German
  • Proceedings of the National Academy of Sciences…
  • 1975
The cytogenetic observation that homologous chromatid interchange occurs in Bloom's syndrome more often than normal prompted an investigation of DNA replication in that rare genetic disorder. Using DNA fiber autoradiography, an estimation was made of the rate of one component of ongoing DNA replication, DNA chain growth. The rate in Bloom's syndrome dermal(More)
Analysis of DNA fiber autoradiograms from Bloom's syndrome skin fibroblasts and blood lymphocytes shows a retarded rate of replication fork movement compared to normal adult controls. Other measurements from the autoradiograms—replication unit length, incidence of bidirectional replication, and degree of initiation synchrony—are normal in Bloom's syndrome(More)
5,6-Dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) inhibits RNA synthesis in L-929 cells (mouse fibroblast line) and HeLa cells (human epitheloid carcinoma line) within 2 min of addition of the compound to the medium. By removing DRB from the medium, the inhibition is promptly and completely reversed after treatment of cells for as long as 1 h or even(More)
Fiber autoradiograms prepared from radioactive DNA of diploid skin fibroblasts and lymphocytes from normal adult humans show patterns of replication of chromosomal DNA that are closely similar to those from other mammalian cells. The rate of replication fork movement is 0.64 μm/min and 0.42 μm/min for fibroblasts and lymphocytes respectively. In both types(More)
Using pulse labeling techniques with [(3)H]thymidine or [(3)H]cytidine, combined with DNA fiber autoradiography, we have investigated the direction and rate of DNA chain growth in mammalian cells. In general, chain elongation proceeds bidirectionally from the common origin of pairs of adjacent replication sections. This type of replication is noted whether(More)
We have used fiber autoradiography to examine the DNA product made in vitro in a lysed cell system. CHO cells were treated with 0.01% Brij-58 and the lysates were incubated at 30 degrees C in a complete reaction mixture for in vitro DNA synthesis with [3H]thymidine triphosphate ([3H]TTP) as the radioactive tracer. Fiber autoradiograms prepared from the DNA(More)
  • R Hand
  • The Journal of cell biology
  • 1975
The effects of inhibition of protein synthesis by the antibiotics cycloheximide and puromycin on the initiation of DNA replication in mouse L cells were studied. Cellular DNA was pulse labeled with [3H]thymidine of high, then of low specific activity and prepared for fiber autoradiography. Autoradiograms containing multiple (up to four) replication units(More)
We have analyzed ongoing DNA replication in ts BN-2, a dna- mutant of BHK-21 cells (Nishimoto et al. '78). At the non-permissive temperature of 39.5 degrees C, inhibition of 3H-thymidine into acid-precipitable material begins 1 to 2 h after the cells are released from a block at the start of the S-phase. The fraction of nuclei incorporating 3H-thymidine is(More)