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Titolo:
Three different calcium wave pacemakers in ascidian eggs
Autore:
Dumollard, R; Sardet, C;
Indirizzi:
Univ Paris 06, Stn Zool, CNRS, Unite Biol Dev UMR 7009, F-06230 Villefranche Sur Mer, France Univ Paris 06 Villefranche Sur Mer France F-06230 ranche Sur Mer, France
Titolo Testata:
JOURNAL OF CELL SCIENCE
fascicolo: 13, volume: 114, anno: 2001,
pagine: 2471 - 2481
SICI:
0021-9533(200107)114:13<2471:TDCWPI>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
WORM CEREBRATULUS-LACTEUS; CA2+ OSCILLATIONS; INOSITOL 1,4,5-TRISPHOSPHATE; ENDOPLASMIC-RETICULUM; SPERM EXTRACT; MOUSE EGGS; SPATIOTEMPORAL DYNAMICS; OOPLASMIC SEGREGATION; MAMMALIAN EGGS; ACINAR-CELLS;
Keywords:
calcium waves; fertilization; inositol (1.4.5)-trisphosphate; cortex; endoplasmic reticulum; pacemaker; eggs; ascidians;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Sardet, C Univ Paris 06, Stn Zool, CNRS, Unite Biol Dev UMR 7009, F-06230 Villefranche Sur Mer, France Univ Paris 06 Villefranche Sur Mer France F-06230 Mer, France
Citazione:
R. Dumollard e C. Sardet, "Three different calcium wave pacemakers in ascidian eggs", J CELL SCI, 114(13), 2001, pp. 2471-2481

Abstract

Calcium wave pacemakers in fertilized eggs of ascidians and mouse are associated with accumulations of cortical endoplasmic reticulurn in the vegetalhemisphere. In ascidians, two distinct pacemakers (PM1 and PM2) generate two series of calcium waves necessary to drive meiosis I and II. Pacemaker PM2 is stably localized in a cortical ER accumulation situated in the vegetal contraction pole. We now find that pacemaker PMI is situated in a cortical ER-rich domain that forms around the sperm aster and moves with it duringthe calcium-dependant cortical contraction triggered by the fertilizing sperm. Global elevations of inositol (1,4,5)-trisphosphate (Ins(1,4,5)P-3) levelsproduced by caged Ins(1,4,5)P-3 or caged glycero-myo-PtdIns(4,5)P-2 photolysis reveal that the cortex of the animal hemisphere, also rich in ER-clusters, is the cellular region most sensitive to Ins(1,4,5)P-3 and acts as a third type of pacemaker (PM3). Surprisingly, the artificial pacemaker PM3 predominates over the natural pacemaker PM2, located at the opposite pole. Microtubule depolymerization does not alter the activity nor the location of the three pacemakers. By contrast, blocking the actomyosin driven cortical contraction with cytochalasin B prevents PM1 migration and inhibits PM2 activity. PM3, however, is insensitive to cytochalasin B. Our experiments suggest that the three distinct calcium wave pacemakers are probably regulated by different spatiotemporal variations in Ins(1,4,5)P-3 concentration. In particular, the activity of the natural calcium wave pacemakers PM1 and PM2 depends on the apposition of a cortical ER-rich domainto a source of Ins(1,4,5)P-3 production in the cortex.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 00:28:56