Cell cycle phase, cellular Ca2+ and development in Dictyostelium discoideum.
In Dictyostelium discoideum, the initial differentiation of cells is regulated by the phase of the cell cycle at starvation. Cells in S and early G2 (or with a low DNA content) have relatively high levels of cellular Ca2+ and display a prestalk tendency after starvation, whereas cells in mid to late G2 (or with a high DNA content) have relatively low levels of Ca2+ and display a prespore tendency. We found that there is a correlation between cytosolic Ca2+ and cell cycle phase, with high Ca2+ levels being restricted to cells in the S and early G2 phases. As expected on the basis of this correlation, cell cycle inhibitors influence the proportions of amoebae containing high or low Ca2+. However, it has been reported that in the rtoA mutant, which upon differentiation gives rise to many more stalk cells than spores (compared to the wild type), initial cell-type choice is independent of cell cycle phase at starvation. In contrast to the wild type, a disproportionately large fraction of rtoA amoebae fall into the high Ca2+ class, possibly due to an altered ability of this mutant to transport Ca2+.
Azhar
M
M
Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India.
Kennady
P K
PK
Pande
G
G
Espiritu
M
M
Holloman
W
W
Brazill
D
D
Gomer
R H
RH
Nanjundiah
V
V
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002449:Cell Aggregation; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D016054:DNA, Protozoan / Q000032:analysis; D004023:Dictyostelium / Q000166:cytology* / Q000502:physiology; D005434:Flow Cytometry; D016195:G2 Phase / Q000502:physiology; D015800:Protozoan Proteins; D016196:S Phase / Q000502:physiology; D013170:Spores
D018797:Cell Cycle Proteins; D016054:DNA, Protozoan; D015800:Protozoan Proteins; C103074:RtoA protein, Dictyostelium discoideum; D002118:Calcium