Two lines of dodecaploid H1 embryonic stem cells, 12H1 and 12H1(-) cells (mouse-originated cells), were established through polyploidization of two hexaploid H1 cells, 6H1 and 6H1(-) cells, which were cultured in L15F10 (7:3) medium with and without leukemia inhibitory factor (LIF), respectively. The G1, S, and G2/M phase fractions of 12H1 and 12H1(-) cells were almost the same as those of 6H1 and 6H1(-) cells, respectively, but the doubling time of cell proliferation was prolonged, suggesting that cell death occurred in 12H1 and 12H1(-)cells. The cell volumes of 12H1 and 12H1(-) cells were about double those of 6H1 and 6H1(-) cells, respectively.
View Article and Find Full Text PDFEtoposide is a specific inhibitor of topoisomerase II, which is an enzyme that enables double-stranded DNA to pass through another double-stranded DNA. Topoisomerase II is a major constituent of chromosome scaffold, existing at appreciable amounts in cells. To examine the effects of etoposide on the cell cycle, hexaploid H1 (ES) cells (6H1 cells) were used with diploid H1 (ES) cells (2H1 cells) as a control.
View Article and Find Full Text PDFObjectives: Tetraploid cells are strictly biologically inhibited from composition of embryos; by the same token, only diploid cells compose embryos. However, the distinction between diploid and tetraploid cells in development has not been well explained. To examine pluripotency of polyploid ES cells, a polyploid embryonic stem (ES)-cell system was prepared.
View Article and Find Full Text PDFHaploid unit-ploidy transition in tetraploid and octaploid mouse H1 (ES) cells (4H1 and 8H1 cells, respectively) during long-term culturing was observed using flow cytometry. The DNA content of 4H1 cells was elevated from 3.5C to 4.
View Article and Find Full Text PDFHexaploid H1 (ES) cells (6H1 cells) were established from octaploid H1 cells (8H1 cells), as were pentaploid H1 cells (5H1 cells). 6H1 cells were compared with 5H1 cells. The number of chromosomes of 6H1 cells was 115, 20 more than the 95 of 5H1 cells.
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