Mouse embryo cells

This suggests that cyclin A2 is not essential for the early embryonic cell cycles. Also D-type cyclins seem to be dispensable for the early mouse embryo cell cycle progression since embryonic stem (ES) cells do not express them at all before differentiation (Savatier et al 1996). We do not know, however, whether the D-type cyclins are also absent in the early embryo. These observations suggest that not only could the first cell cycles of the mouse embryo have specific modifications, but also further embryonic cell cycles are specifically modified as well. Mammalian embryonic cell cycles are probably modified often during development. Such studies could allow us to determine a profile of a minimal cell cycle in mammals which must, however, be much more complex than a simple S M phase embryonic cell cycle of amphibians or insects. 

Cuthbertson KS, Whittingham DG, Cobbold PH 1981 Free Ca2+ increases in exponential phases during mouse oocyte activation. Nature 294 754—757 Day ML, Johnson MH, Cook DI 1998 A cytoplasmic cell cycle controls the activity of a K+ channel in pre-implantation mouse embryos. EMBO J 17 1952—1960 Flach G, Johnson MH, Braude PR, Taylor RA, Bolton VN 1982 The transition from maternal to embryonic control in the 2-cell mouse embryo. EMBO J 1 681-686 Howlett SK 1986 A set of proteins showing cell cycle-dependent modification in the early mouse embryo. Cell 45 387-396... 

Landolph JR (1985) Chemical transformation of C3H/10T1/2 Cl 8 mouse embryo cells historical background, assessment of the transformation assay and evaluation and optimization of the transformation assay protocol. In IARC Scientific Publication No 67, pp 185-198... 

Osterman JV, Waddell A, Aposhian HV. DNA and gene therapy uncoating of polyoma pseudovirus in mouse embryo cells. Proc Natl Acad Sci USA 1970 ... 

Miura T, Patiemo SR, Sakuramoto T. 1989. Morphological and neoplastic transformation of C3H/10tl/2 Cl 8 mouse embryo cells by insoluble carcinogenic nickel compounds. Environ Mol Mutagen 14 65-78. 

Miller, R. and Hall, E.J. (1978). "X-ray dose fractionation and oncogenic formations in cultured mouse embryo cells, Nature 272, 58. 

Reznikoff, C.A., Bertram, J.S., Brankow, D.W., and Heidelberger, C. (1973) Quantitative and qualitative studies of chemical transformation of cloned C3H mouse embryo cells sensitive to postconfluence inhibition of cell division, Cancer Res. 33,3230. 

Patierno, S.R., Lehman, N.L., Henderson. B.E. Landolph, J.R. (1989) Study of the ability of phenacetin, acetaminophen, and aspirin to induce cytotoxicity, mutation and morphological transformation in CJH/IOT A clone 8 mouse embryo cells. Cancer Res., 49, 1038-1044... 

TCM, Cell transformation, C3H 1 OT T mouse embryo cells in vitro - NT 5 Schechtman et al. 

Pretazettine (395) has been the subject of numerous biological studies, and it has been shown to exhibit a number of interesting activities (96,97,101,178-187). For example, 395 was found to inhibit HeLa cell growth as well as protein synthesis in eukaryotic cells by interfering with the peptide bond formation step (97,101). Furthermore, pretazettine inhibited the purified RNA-dependent DNA polymerase (reverse transcriptase) from avian myeloblastosis virus, a typical C-type virus (178), in an unusual fashion since it physically combined with the polymerase enzyme itself rather than interacted with the nucleic acid template. Pretazettine also exhibited antiviral activity against the Rauscher leukemia virus in mouse embryo cell cultures by suppressing viral replication (179). 

Identification of DNA-Reactive Metabolites Generated in a Target Tissue, Mouse Skin, In Vivo. Our initial studies focused on activation of DMBA in mouse embryo cells in culture because of the ease of isolation of sufficient DNA for adduct characterization. The cells were exposed to DMBA and the isolated DNA enzymatically hydrolyzed to deoxyribonucleosides. DMBA-deoxyribonucleoside adducts were characterized by fluorescence measurements (11,22), by photosensitivity studies (12) and by column chromatography (23,24). These studies provided evidence that the DNA-reactive metabolite generated in these cells is a bay region dihydrodiol epoxide. The enzymatic steps in this activation pathway (Figure 1) involve oxidation of DMBA by mixed function oxidases to a 3,4-epoxide which is converted by epoxide hydrase to a 3,4-dihydro-diol. This is, in turn, oxidized by mixed function oxidases to the dihydrodiol epoxide. 

Figure 2. Sephadex LH-20 column chromatography of DMBA-deoxyribo-nucleoside adducts formed by enzymatic digestion of DNA from mouse embryo cells exposed to [l Cj-DMBA (0.2 yg/ml) for 24 h ( - ) and of DNA from the skin of female NIH Swiss mice treated with [3h]-DMBA (10 yg/mouse) for 24 h (0-0). The arrow denotes the position of elution of an added uv-absorbing marker 4-(p-nitrobenzyl)pyridine. "Reproduced with permission from Ref. 15. Copyright 1980, IRL Press".

In contrast, we did not find these concentration-dependent qualitative changes when activation occurred in intact cellular systems (16). We examined the adducts formed in mouse embryo cells in culture and in mouse skin ijri vivo over 40- and 100-fold DMBA concentration ranges, respectively, and found quantitative, but no qualitative, changes in binding (16). At all concentrations, activation appeared to be through the bay region dihydrodiol epoxide pathway. The cellular systems are physically very different from the homogenate systems and it is difficult to... 

Mouse embryo cells (11,12,23) Hamster embryo cells Tl6T Rat liver cells (13)... 

The relative amounts of syn and anti adducts produced in mouse embryo cells did not vary substantially with DMBA concentration (20). However, we found a dramatic difference in the relative amounts of these adducts when the dose of DMBA applied to mouse skin was varied (jl). Figure 9 shows the HPLC elution profiles for adducts formed at a low dose of 14 nmol [ HJ-DMBA. Peaks A,C and D are present in approximately equal amounts, i.e. 29, 21 and 22% of total radioactivity, respectively. However, at a 100-fold higher dose of 1400 nmol, peak C has increased to 39% while A and D have decreased to 13% and 9%. These results indicate that the formation of syn-bay region dihydrodiol epoxide adducts is favored at high doses. Due to this, the total binding to deoxyadenosine (peaks C and D) also increases with dose and ranges from 27% to 48% of the total DNA binding. 

If a strip of cells is removed from a confluent monolayer of untransformed cells (e.g. 3T3 mouse embryo cells) then the cells at the edge of the wound are stimulated to synthesise DNA and divide. They quickly colonise the unoccupied area of the wound. This phenomenon known as topo inhibition (Dulbecco, 1970) is now explained by the presence in cells on the edge of the wound of an increased surface area exposed to the medium (i.e. neighbouring cells have been removed) (Stoker, 1973 Dulbecco and Elkington, 1973). 

W. R. Waldrip, E. K. Bikolf, P. A. Hoodless, J. L. Wrana, and E. J. Robertson. Smad2 signaling in extra-embryonic tissues determines anterior-posterior polarity of the early mouse embryo. Cell, 92, 797-808, 1998. 

Jaenisch R. Retroviruses and embryogenesis Microin-jection of Moloney leukemia virus into midgestation mouse embryos. Cell 1980 19 181-8. 

Tor ado GJ Green H, (1963) Quantitative studies of the growth of mouse embryo cells in culture and their development into established lines. Journal of Cell Biology 17 299-313. 

Loo DT, Fuquay JI, Rawson CL Barnes DW (1987) Extended culture of mouse embryo cells without senescence inhibition by serum. Science 236 200-202. 

Landolph JR, Verma A, Ramnath J, and Clemens F (2002) Molecular biology of deregulated gene expression in transformed C3H/10T1/2 mouse embryo cell lines induced by specific insoluble carcinogenic nickel compounds. Environmental Health Perspectives 110(Suppl. 5) 845-850. 

Patierno SR, Banh D, and Randolph JR (1988) Transformation of C3H/10T1/2 mouse embryo cells to focus formation and anchorage independence by insoluble lead... 

Propylene oxide is mutagenic in several microorganisms and in Drosophila. It induces sister chromatid exchanges and chromosomal aberrations, as well as DNA damage (single- and double-strand breaks) in human cells. Propylene oxide induces neoplastic cell transformation in mouse embryo cells. 

Fig. 8. Activity of distamycin derivatives on mouse embryo cells infected or not with...

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