Microinjection of Ca2+ store-enriched microsome fractions to dividing newt eggs induces extra-cleavage furrows via inositol 1,4,5-trisphosphate-induced Ca2+ release.
The cleavage signal transferred to the future cleavage cortex during anaphase has been proposed as "cleavage stimulus," but no signal has proved to induce cleavage furrows. The local Ca2+ transient along the cleavage furrow has been reported, but the Ca2+ source has remained unknown. To address these questions, we studied functions of Ca2+ stores in dividing newt eggs and found that microinjection of the Ca2+ store-enriched microsome fraction to the dividing newt egg induced a local extra-cleavage furrow at the injection site in 64-67% of the injected newt eggs while coinjection with inositol 1,4, 5-trisphosphate receptor (IP(3)R) antagonists heparin or anti-type 1-IP(3)R antibody clearly suppressed this induction (5 and 11% in induction rates, respectively). Injection of cerebellar microsomes from the type 1-IP(3)R-deficient mice induced extracleavage furrows albeit at a low rate (19%). Our observations strongly suggest that Ca2+ stores with IP(3)R induce and position a cleavage furrow via IP(3)-induced Ca2+ release (IICR) as Ca(2+)-releasing machinery and putative cleavage stimulus itself.
Mitsuyama
F
F
Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, 108-8639, Japan. mituyama@ims.u-tokyo.ac.jp
Sawai
T
T
Carafoli
E
E
Furuichi
T
T
Mikoshiba
K
K
D000705:Anaphase; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D016466:CHO Cells; D002118:Calcium / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism; D002455:Cell Division; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D006224:Cricetinae; D005260:Female; D049452:Green Fluorescent Proteins; D006493:Heparin / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D051379:Mice; D008845:Microinjections; D008861:Microsomes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D010063:Ovum / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012455:Salamandridae; D014162:Transfection; D015053:Zygote / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D000906:Antibodies; D015220:Calcium Channels; D006063:Chorionic Gonadotropin; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008164:Luminescent Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D015544:Inositol 1,4,5-Trisphosphate; D006493:Heparin; D000252:Calcium-Transporting ATPases; D002118:Calcium