Initiation of deoxyribonucleic acid replication at the nuclear membrane in human cells

Comings, David E.; Kakefuda, Tsuyoshi

doi:10.1016/0022-2836(68)90290-8

Cited by 182 publications

(30 citation statements)

References 17 publications

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“…In general, DNA synthesis takes place just before chromatin condensation. In relation to the site of DNA synthesis, it has been reported the synthesis occurs initially on the nuclear envelope (Comings and Kakefuda 1968). The present experiment confirmed their result.…”

Section: Methodssupporting

confidence: 90%

“…The silver grains, which represent the 3H-TdR incorporation, are mainly found on chromatin condensed region but occasionally found also on chromatin dispersed area. Concerning of the site of DNA replication, Comings and Kakefuda (1968) suggested that DNA synthesis in human amnion cells may be initiated at the nuclear envelope. Moreover, Comings and Okada (1970 a, b) demonstrated that the aggregates of chromatin fiber attach to the annuli of the nuclear envelope, and that chromosomes condense onto the inner surface of the nuclear envelope.…”

Section: Pronase Digestionmentioning

confidence: 99%

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Ultrastructural Studies on the Nuclear Changes in Insufficient-stimulated Eggs of the Sea Urchin

Uto

Tsukahara

1977

CYTOLOGIA

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Section: Methodssupporting

confidence: 90%

Section: Pronase Digestionmentioning

confidence: 99%

Ultrastructural Studies on the Nuclear Changes in Insufficient-stimulated Eggs of the Sea Urchin

Uto

Tsukahara

1977

CYTOLOGIA

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“…Our results and conclusions on sites of initiation of DNA replication agree with those of Williams and Ockey (6) and disagree with those of Comings and Kakefuda (5). Concerning this disagreement we can only reiterate the importance of synchronization procedures that require a minimum time of arrest of cells at the G1-S border and completely eliminate the possibility that any cells in the population may be in the later parts of the S period.…”

Section: For Review)contrasting

confidence: 47%

Initiation and Continuation of DNA Replication Are Not Associated with the Nuclear Envelope in Mammalian Cells

Wise

Prescott

1973

Proc. Natl. Acad. Sci. U.S.A.

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For determination of whether DNA replication is initiated at the nuclear envelope, synchronizedChinese hamster ovary cells labeled with [3HIthymidine were examined by electron microscope radioautography. The cells were synchronized initially by mitotic shake-off and held at the G1-S border by 5-fluorodeoxyuridine plus amethopterin. Cells were fixed at 1, 5, 10, and 30 min after the inhibitors were counteracted with [3H]thymidine.Radioautographic silver grains in each case were present over the more central parts of nuclei and were generally absent from the region of the nuclear envelope. We conclude that neither initiation nor continuation of DNA replication is associated with the nuclear envelope.An important facet of the problem of DNA replication in eukaryotes is whether initiation of replication occurs at points of attachment of the chromosome to the nuclear envelope. The question arises in part because of the evidence that the replicons of prokaryotic chromosomes initiate and then continue replication at points of attachment to the plasma membrane (see, for example, refs. 1-3). Several kinds of experiments on prokaryotes suggest that the enzymes and other factors necessary for DNA replication may form a complex that remains associated with the plasma membrane during chromosome replication (see ref. 4 for review).In studies of human amnion cells, Comings and Kakefuda (5) concluded from electron microscope radioautography that DNA replication is initiated at the nuclear envelope at the beginning of the period of DNA synthesis (S period). Contrary to this conclusion, Williams and Ockey (6) have obtained evidence by electron microscope radioautography that DNA replication at the beginning of the S period is not initiated at the nuclear envelope in Chinese hamster cells. According to them and to Huberman et al. (7), DNA synthesis late in the S period is highly concentrated near the nuclear envelope; this result is to be expected because replication of DNA in heterochromatin dominates the later part of the S period, and heterochromatin tends to be tightly condensed against the nuclear envelope. The results of Williams and Ockey (6) are to some degree supported by work of Erlandson and de Harven (8) for HeLa cells and of Blondel (9) for KB cells. In another eukaryote, Amoeba proteus, DNA replication is probably not associated with the nuclear envelope at any time during the S period (10).To answer the question of association of initiation or continuation of replication with the nuclear envelope in mammalian cells requires a very high degree of synchrony of the cultured cells. Many of the agents used for synchronization are incompletely effective. Ockey (11), for example, showed that amethopterin does not block cells from entering the S period. A high thymidine concentration (thymidine block) also fails to block cells at the G1-S border (12).We describe experiments here that minimize the shortcomings of current methods of synchronization. Our results strongly indicate that DNA replication is not initiated...

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“…It is therefore reasonable to conclude that quali-400 THE JOURNAL OF CELL BIOLOGY • VOLUME 46,1970 tatively as well as quantitatively the nuclear membrane lipids are representative for the total nuclear lipids. This does not exclude, of course, the possibility that a small part of the lipoprotein of the nuclear envelope can be present in close association with the chromatin, since such interactions might be prerequisites for DNA synthesis as is suggested by the work of Comings (10) and Comings and Kakefuda (11) . In preliminary experiments in our laboratory, however, only small amounts of phospholipid could be detected in isolated chromatin which had been prepared from nuclei of pig liver using a combination of the methods of Marushige and Bonner (38) Since the over-all ratio of total phospholipid to DNA in whole nuclei generally does not exceed 0 .2 (w/w), the ratio of phospholipid to DNA included in such residues should be very low in quantitative experiments .…”

Section: Discussionmentioning

confidence: 98%

Nuclear Membranes From Mammalian Liver

Kleinig

1970

The Journal of Cell Biology

112

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The qualitative and quantitative lipid composition of nuclei and nuclear membranes from pig and rat liver were determined . These determinations were compared with the corresponding data obtained for microsomes from the same material after similar treatments . The results indicate that, at least, by far the major part of the nuclear lipids is located in the membranes of the nuclear envelope . The phospholipid pattern of the nuclear membranes and the endoplasmic reticulum (ER) membranes in general is widely identical in both species . As a striking difference in the lipid composition, however, a fourfold increase of esterified cholesterol in the nuclear membranes was found . In a quantitative approach the ratio of total surface area of the nuclear lipids to the total surface area of the nuclear envelope membranes was calculated as being 3 .6, a value which fairly approximates the requirements of a bimolecular lipid leaflet model .

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Initiation of deoxyribonucleic acid replication at the nuclear membrane in human cells

Cited by 182 publications

References 17 publications

Ultrastructural Studies on the Nuclear Changes in Insufficient-stimulated Eggs of the Sea Urchin

Ultrastructural Studies on the Nuclear Changes in Insufficient-stimulated Eggs of the Sea Urchin

Initiation and Continuation of DNA Replication Are Not Associated with the Nuclear Envelope in Mammalian Cells

Nuclear Membranes From Mammalian Liver

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