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Accumulation of cells with 4N DNA content at nonpermissive temperature in rat embryo diploid cells transformed by tsA mutant of simian virus 40
Author(s) -
Okuda Atsuyuki,
Tamura Hideaki,
Shimura Hideo,
Kimura Genki
Publication year - 1986
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041270218
Subject(s) - thermolabile , biology , colcemid , embryo , microbiology and biotechnology , mutant , dna , ploidy , dna synthesis , virus , cell culture , virology , genetics , biochemistry , gene , enzyme
Primary rat embryo cells were transformed by a tsA mutant ( tsA 640) of simian virus 40 (SV40). Proliferation of all four independent diploid transformants was suppressed at a nonpermissive temperature (40.3°C), being accompanied by a marked increase in the fraction of cells with a 4N DNA content (a 4N peak in the flow cytofluorogram). However, in this case, the fraction of cells with a 2N DNA content (a 2N peak in the flow cytofluorogram) was preserved. Both effects (suppression of proliferation and increase in the 4N peak) diminished when transformed cells were superinfected with wild‐type SV40. The increased 4N peak was preserved, albeit not completely, for at least 24 hours, when cells were further incubated in the presence of hydroxyurea at the nonpermissive temperature. On the other hand, the preserved 2N peak all but disappeared within 24 hours, when cells were further incubated in the presence of colcemid at the nonpermissive temperature. These results suggest that the thermolabile large T antigen of SV40 directly or indirectly induces an accumulation of cells with a 4N DNA content, at the nonpermissive temperature, by prolonging the G2 (and/or late S) period.