Induction of cell replication

Yasuda, Hiroshi; Hirokawa, Yasuko

doi:10.1016/0014-4827(68)90485-0

Cited by 56 publications

(16 citation statements)

References 10 publications

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“…Enami, personal communication), the C3H2K cell line from newborn C3HIHe mouse kidney (Yoshikura and Hirokawa, 1968), or the BALB 3T3 A31 cell line from BALB/c mouse embryo (Aaronson and Todaro, 1968). When bone marrow cells were seeded onto the cell layers of these lines, only a small number of CFU-S survived 7 days, contrary to the results obtained with MC3T3-G2/PA6 cells (Table 2).…”

Section: Ability Of Other Cell Lines To Promote In Vitro Hemopoiesiscontrasting

confidence: 71%

A new preadipose cell line derived from newborn mouse calvaria can promote the proliferation of pluripotent hemopoietic stem cells in vitro

Kodama

Amagai

Koyama

et al. 1982

Journal Cellular Physiology

136

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A clonal preadipose cell line MC3T3-G2/PA6, established from newborn mouse calvaria, responds to glucocorticoids and converts to adipose cells in a fashion similar to bone marrow preadipocytes. We investigated the effect of the cells on in vitro hemopoiesis of mouse bone marrow cells by cocult~vation. When bone marrow cells were inoculated into confluent cultures of MC3T3-G2/PA6 cells (104-106 celM25-cm2 flask), the number of hemopoietic stem cells (CFU-S) significantly increased during 7-day cultivation in proportion to inoculum size. Under these conditions, active replication of CFU-S was maintained for several weeks until MC3T3-G2/PA6 cell layers detached from the substratum. This capacity of the MC3T3-G2/PA6 line was unique because other established cell lines, including the MTF preadipose line, failed to support CFU-S growth. When bone marrow cells were not allowed to contact the MC3T3-GZiPA6 cell layer, only a small number of CFU-S survived for 7 days. Moreover, MC3T3-G2/PA6 cell-conditioned medium did not show any growth-promoting activity for CFU-S. These results indicate that the MC3T3-G2/PA6 cell line has the ability to promote the proliferation of CFU-S through a short range cell-to-cell interaction by providing an in vitro microenvironment probably similar to that for in vivo hemopoiesis.

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Section: Ability Of Other Cell Lines To Promote In Vitro Hemopoiesiscontrasting

confidence: 71%

A new preadipose cell line derived from newborn mouse calvaria can promote the proliferation of pluripotent hemopoietic stem cells in vitro

Kodama

Amagai

Koyama

et al. 1982

Journal Cellular Physiology

136

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“…On the other Temperature-Sensitive Transformed Cells 217 hand, the piled-up cells seen in the 360 culture are more spherical and have a rough surface due to a larger number of microvilli (Fig. 2B) (24,25), although addition of excess serum may allow them to continue to synthesize DNA and "pile-up" at high cell density (26). On the other hand, transformed fibroblasts frequently continue to synthesize DNA and pile-up when the culture reaches a high cell density, even at low serum concentrations (26).…”

Section: Resultsmentioning

confidence: 99%

Temperature-sensitive mutants of chemically transformed epithelial cells.

Yamaguchi¹,

Weinstein²

1975

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

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The first temperature-sensitive mutants of epithelial cells transformed with chemical carcinogens have been isolated. Like the wild-type transformed parental cells, the mutants readily grow in agar suspension at 360, but in contrast to the wild type, they do not do so at 400. Detailed studies of one of these mutants, TS-223, indicate that at high temperature it also has reduced cloning efficiency in monolayer culture and a lower saturation density. Scanning electron microscopy revealed that at 40°confluent cultures of TS-223 consist of a monolayer of generally ilat polygonal cells, whereas 360 cultures contain many patches of piled-up cells that are spherical and have rougher surface membranes. All of these cellular changes are reversible with upward or downward temperature shifts. The temperature-sensitive lesion appears to reside in a host cell gene which modulates expression of the transformed cell phenotype. These mutants may provide a useful system for elucidating the minimal biochemicai changes required for expression of the transformed phenotype in epithelial cells.Mutants that are temperature sensitive (TS) in the expression of cell transformation afford a powerful tool for analyzing mechanisms of transformation since one can, at will, turn off or on the tumor phenotype. Several TS mutants of RNA and DNA tumor viruses have been isolated (1-10). The cells transformed by these viruses have characteristics of normal cells when grown at high temperature and of tumor cells when grown at lower temperature. Cell mutants of this type have also been isolated from 3T3 mouse fibroblasts transformed by simian virus 40 (11).It is important to develop similar mutants of cells transformed by chemical carcinogens, since the phenotype of chemically transformed cells may differ from that of virally transformed cells. Aside from the cold-sensitive chemically transformed BHK cells described by DiMayorca et al. (12), there are no published reports of TS mutants in cells transformed by chemical carcinogens.In the present study we report the isolation of five mutants of epithelial cells transformed by the carcinogen, N-acetoxyacetylaminofluorene, which are temperature sensitive in the maintenance of several properties associated with transformation. Our laboratory has emphasized the use of epithelial cells because about 80% of human tumors arise from epithelial tissues (13), and the growth properties of tumorigenic epithelial cultures (14-16) differ in several respects from those of transformed fibroblast cultures (17). Because of their epithelial origin, W-8 cultures do not display the criss-cross growth pattern seen with transformed fibroblasts (17) and they show "piling up" only when kept as confluent cultures for several days and only when the growth medium is changed repeatedly.The growth medium used throughout these experiments, unless stated otherwise, was Dulbecco's modification of Eagle's medium (GIBCO) supplemented with 10% fetal calf serum. This medium was also used when cells were grown in 0.4% agar suspens...

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“…Two different methods were used to synchronize the cells to the S phase: (a) serum addition to the cultures of serum-253 starved Go-phase C3H2K cells [28] and (b) arrest of the start of DNA replication by aphidicolin treatment, resulting in the accumulation of Ehrlich cells in G1/S phase [32]. Fig.…”

Section: Increase In D N a Replicase In Cells During The Early Sphasementioning

confidence: 99%

Activity levels of mouse DNA polymerase alpha-primase complex (DNA replicase) and DNA polymerase alpha, free from primase activity in synchronized cells, and a comparison of their catalytic properties

1986

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To asses the possible roles of the two active forms of mouse DNA polymerase a : primase -DNA-polymerase a complex (DNA replicase) and DNA polymerase c1 free from primase activity (7.3s polymerase), in nuclear DNA replication the correlation of their activity levels with the rate of nuclear DNA replication was determined and a comparison made of their catalytic properties. The experiments using either C3H2K cells, synchronized by serum starvation, or Ehrlich culture cells, arrested at the S phase by aphidicolin, showed DNA replicase to increase in cells in the S phase to at least six times that of the Go-phase cells but 7.3s polymerase to increase but slightly in this phase. This increase in DNA replicase activity most likely resulted from synthesis of a new enzyme, as shown by experiments using a specific monoclonal antibody, aphidicolin and cycloheximide. Not only with respect to the presence or absence of primase activity, but in other points as well the catalytic properties of these two forms were found to differ; DNA replicase preferred the activated calf thymus DNA with wide gaps of about 100 nucleotides long as a template-primer, while the optimal gap size for 7.3s polymerase was 40 -50 nucleotides long. Size analysis of the products synthesized on M13 single-stranded circular DNA with a single 17-nucleotide primer by DNA replicase and 7.3s polymerase suggested the ability of DNA replicase to overcome a secondary structure formed in single-stranded DNA to be greater than that of 7.3s polymerase.Among three major DNA polymerases there is much evidence indicating the involvement of DNA polymerase c1 in the nuclear DNA replication process [l -31. Moreover, studies using selective inhibitors of DNA polymerase a, particularly aphidicolin, show that DNA polymerase c1 as well as DNA polymerase fl possibly participates in the repair DNA syn-

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Induction of cell replication

Cited by 56 publications

References 10 publications

A new preadipose cell line derived from newborn mouse calvaria can promote the proliferation of pluripotent hemopoietic stem cells in vitro

A new preadipose cell line derived from newborn mouse calvaria can promote the proliferation of pluripotent hemopoietic stem cells in vitro

Temperature-sensitive mutants of chemically transformed epithelial cells.

Activity levels of mouse DNA polymerase alpha-primase complex (DNA replicase) and DNA polymerase alpha, free from primase activity in synchronized cells, and a comparison of their catalytic properties

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