Intracellular free calcium level and its response to cAMP stimulation in developing Dictyostelium cells transformed with jellyfish apoaequorin cDNA.
A new method is described for measuring intracellular free calcium concentrations, [(Ca2+)i], in the cells of Dictyostelium discoideum transformed with apoaequorin cDNA of the jellyfish, Aequorea victoria. Aequorin, a calcium-specific indicator, was regenerated in vivo from apoaequorin produced in the cells by incubation with coelenterazine. The results showed that [(Ca2+)i] in developing cells markedly increases at the aggregation stage and again at the culmination stage after a temporary drop at the migration stage. Except for the vegetative stage, the cells at all stages of development exhibit a sharp transient increase in [(Ca2+)i] upon stimulation with a cAMP (50 nM) pulse, high responses being observed at the migration and culmination stages. Separated prestalk cells of migrating slugs contain more than twice as much [(Ca2+)i] and show three times as large a response to cAMP stimulation as prespore cells.
Saran
S
S
National Institute for Basic Biology, Okazaki, Japan.
Nakao
H
H
Tasaka
M
M
Iida
H
H
Tsuji
F I
FI
Nanjundiah
V
V
Takeuchi
I
I
D000331:Aequorin / Q000235:genetics*; D000818:Animals; D001059:Apoproteins / Q000235:genetics*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D002454:Cell Differentiation; D000242:Cyclic AMP / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics*; D004023:Dictyostelium / Q000187:drug effects / Q000378:metabolism*; D049449:Luminescence; D011994:Recombinant Proteins / Q000235:genetics; D037401:Scyphozoa / Q000235:genetics*; D014162:Transfection
D001059:Apoproteins; D018076:DNA, Complementary; D011994:Recombinant Proteins; C060014:apoaequorin; D000001:Calcimycin; D000331:Aequorin; D000242:Cyclic AMP; D002122:Calcium Chloride; D002118:Calcium