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Titolo:
ACTIVATION OF NEWT EGGS IN THE ABSENCE OF CA2+ ACTIVITY BY TREATMENT WITH CYCLOHEXIMIDE OR D2O
Autore:
IWAO Y; MASUI Y;
Indirizzi:
YAMAGUCHI UNIV,FAC SCI,DEPT BIOL SCI YAMAGUCHI 753 JAPAN UNIV TORONTO,DEPT ZOOL TORONTO ON M5S 1A1 CANADA
Titolo Testata:
Development, growth & differentiation
fascicolo: 6, volume: 37, anno: 1995,
pagine: 641 - 651
SICI:
0012-1592(1995)37:6<641:AONEIT>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
CYTOSTATIC FACTOR CSF; METAPHASE-II ARREST; XENOPUS-LAEVIS; PROTEIN-SYNTHESIS; CELL-CYCLE; MEIOTIC MATURATION; MOUSE OOCYTES; CYTOPLASMIC FACTOR; AMPHIBIAN EGGS; FERTILIZATION;
Keywords:
CA2+ ION; EGG ACTIVATION; MICROTUBULES; PROTEIN PHOSPHORYLATION; PROTEIN SYNTHESIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
47
Recensione:
Indirizzi per estratti:
Citazione:
Y. Iwao e Y. Masui, "ACTIVATION OF NEWT EGGS IN THE ABSENCE OF CA2+ ACTIVITY BY TREATMENT WITH CYCLOHEXIMIDE OR D2O", Development, growth & differentiation, 37(6), 1995, pp. 641-651

Abstract

Unfertilized eggs of urodeles that exhibit physiological polyspermy are difficult to activate by ordinary egg-activating agents, such as pricking and Ca2+ ionophores, that easily activate monospermic anuran eggs. Therefore, we have tested the effects of other agents that cause egg activation in non-amphibian species in order to investigate the mechanism of egg activation in urodeles. We have found that cycloheximide(a protein synthesis inhibitor), D2O (that induces microtubule polymerization) and 6-DMAP (a protein kinase inhibitor) caused activation ofunfertilized eggs of the newt, Cynops pyrrhogaster. The cell cycle, arrested at meiotic metaphase II, was resumed to form the second polar body accompanied by a loss of maturation promoting factor and cytostatic factor activity. The treated eggs underwent abnormal cleavage. These results indicate that protein synthesis followed by protein phosphorylation is necessary to maintain M phase in unfertilized Cynops eggs. Unfertilized eggs failed to be activated by pricking, but were activated by the ionophore A23187, but only at a concentration 30 times higher than that required to activate Xenopus eggs. Eggs whose intracellular Ca2+ ions had been chelated by BAPTA could also be activated by either cycloheximide or D2O. Cycloheximide- as well as 6-DMAP-induced egg activations were not inhibited by nocodazole, a microtubule-depolymerizing agent. These results suggest that the inhibition of synthesis andphosphorylation of short-lived proteins acts as an egg activation mechanism, downstream of the site of Ca2+ action and independently of microtubule polymerization.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 22:19:00