Increase of Calcium Levels at Interphase in NIH 3T3 Cells

The fluorescent calcium ion indicator dye Fluo-3 and DNA-binding dye Hoechst 33342 were employed to determine, in a quantitative microspectrofluorometric study, the intracellular calcium ion concentration ([Ca~(2+)]_i) and the DNA content of individual living NIH3T3 cells. The well-separated excitation and emission properties of these dyes allowed us to establish for each cell both the phase of the cell cycle using DNA content and [Ca~(2+)]_i. We found that the transition from G_1, through S, to the G_2 phase is accompanied by a two-fold increase in [Ca~(2+)]_i. The [Ca~(2+)]_i was inhomologous in each phase of the interphase (G_1, S and G_2) although [Ca~(2+)]_i in the S and G_2 phases was never lower than certain threshold values in the G_1 and S phases respectively. [Ca~(2+)]_i in G_0 cells was lower than that in G_2 cells. These changes in [Ca~(2+)]_i suggest that [Ca~(2+)]_i may be an import regulator of cell cycle progression.     

NIH 3T3细胞中钙离子在间期内增加

本文利用钙离子荧光指示剂Fluo-3和结合DNA的荧光染料Hoechst33342对NIH3T3活细胞进行染色,并用显微荧光分光光度计测定单个细胞中DNA含量和细胞内钙离子浓度,测定出细胞从G_1期经S期到G_2期,细胞内钙离子浓度几乎增加了一倍,每个细胞周期时相中的细胞钙离子浓度是非均一的,但S和G_2期细胞中钙离子浓度从不低于G_1和S期细胞中钙离子的一定浓度,G_0期细胞中钙离子浓度也是非均一的,其中一些G_0期细胞低于G_1期细胞中的钙离子浓度,这种钙离子浓度在细胞周期中的变化可能与细胞周期的调控有关。