TY - JOUR
T1 - "Spiral asters" and cytoplasmic rotation in sea urchin eggs
T2 - Induction in strongylocentrotus purpuratus eggs by elevated temperature
AU - Schroeder, Thomas E.
AU - Battaglia, David E.
PY - 1985/4/1
Y1 - 1985/4/1
N2 - "Spiral asters" composed of swirls of subcortical microtubules were recently described in fertilized eggs of the sea urchin Strongylocentrotus purpuratus. In our study, these structures did not occur at culture temperatures below 16°C. When the culture temperature was elevated, however, "spiral asters" routinely appeared during a susceptible period before mitotic prophase when the sperm aster-diaster normally exists. A massive and protracted rotation of the cytoplasm (excluding an immobile cortex and perinuclear region) began within 1 min of exposure to elevated temperature. Fibrils of the "spiral aster" could be seen within this rotating mass even by bright-field microscopy. The identity of microtubules in these structures was confirmed by indirect immunofluorescence microscopy. A mechanistic association between "spiral aster" formation and cytoplasmic rotation was indicated by the simultaneous inhibitory effects of microtubule and dynein poisons. Inhibitors of microfilaments, however, had no effect. We infer that elevated temperature induces unique changes in the microtubules of the pre-prophase sperm aster-diaster, resulting in cytoplasmic rotation and the spiral configuration of microtubules. Comparative cytological evidence supports the idea that "spiral asters" do not normally occur in fertilized sea urchin eggs. Biogeographic evidence for S. purpuratus indicates that fertilization and development naturally occur below 15°C, hence "spiral asters" in eggs of this species should be regarded as abnormalities induced in the laboratory by unnaturally elevated temperatures.
AB - "Spiral asters" composed of swirls of subcortical microtubules were recently described in fertilized eggs of the sea urchin Strongylocentrotus purpuratus. In our study, these structures did not occur at culture temperatures below 16°C. When the culture temperature was elevated, however, "spiral asters" routinely appeared during a susceptible period before mitotic prophase when the sperm aster-diaster normally exists. A massive and protracted rotation of the cytoplasm (excluding an immobile cortex and perinuclear region) began within 1 min of exposure to elevated temperature. Fibrils of the "spiral aster" could be seen within this rotating mass even by bright-field microscopy. The identity of microtubules in these structures was confirmed by indirect immunofluorescence microscopy. A mechanistic association between "spiral aster" formation and cytoplasmic rotation was indicated by the simultaneous inhibitory effects of microtubule and dynein poisons. Inhibitors of microfilaments, however, had no effect. We infer that elevated temperature induces unique changes in the microtubules of the pre-prophase sperm aster-diaster, resulting in cytoplasmic rotation and the spiral configuration of microtubules. Comparative cytological evidence supports the idea that "spiral asters" do not normally occur in fertilized sea urchin eggs. Biogeographic evidence for S. purpuratus indicates that fertilization and development naturally occur below 15°C, hence "spiral asters" in eggs of this species should be regarded as abnormalities induced in the laboratory by unnaturally elevated temperatures.
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U2 - 10.1083/jcb.100.4.1056
DO - 10.1083/jcb.100.4.1056
M3 - Article
C2 - 3156865
AN - SCOPUS:0021960236
SN - 0021-9525
VL - 100
SP - 1056
EP - 1062
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 4
ER -