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Phospholipase C in mouse oocytes: Characterization of β and γ isoforms and their possible involvement in sperm-induced Ca2+ spiking

par Dupont, Geneviève ;McGuinness, Orla M.;Johnson, Michael K.;Berridge, Michael;Borgese, Franck
Référence Biochemical journal, 316, 2, page (583-591)
Publication Publié, 1996-06

Article révisé par les pairs

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Résumé :

This study involved an investigation of the role of phospholipase C (PLC) in generating repetitive Ca2+ spikes at fertilization. Using a PCR-based strategy we have demonstrated that mouse oocytes have mRNA coding for PLCβ1, PLCβ3 and PLCγ isoenzymes. Furthermore, immunodetection of PLCγ1 using monoclonal antibodies reveals that PLCγ1 protein is present in mature mouse oocytes, ruling out the possibility that mRNA was being transcribed but not expressed. We were unsuccessful at detecting the presence of PLCβ protein, but the presence of this isoform can be inferred from functional studies. The PLC inhibitor, U73122, exerted an inhibitory effect on oocytes activated by spermatozoa or acetylcholine at concentrations of 10 and 30 μM respectively, while its inactive analogue had no effect. The soluble tyrosine kinase inhibitors, genistein (100 μM), herbimycin (10 μM) and geldanamycin (0.6 μM) which could affect signalling through PLCγ hindered but never completely inhibited Ca2+ spiking in response to fertilization. We conclude that the activation of PLC to generate InsP3 may play a critical role in fertilization.