A nucleic acid sequence, including an isolated, purified or recombinantnucleic acid sequence, comprises: (a) a nucleic acid sequence encoding apolypeptide encompassed by the present invention, namely, a PLC zeta；PLC.zeta. amino acid sequence, capable of triggering calcium oscillations inoocytes； (b) a sequence substantially homologous to or that hybridizes tosequence (a) under stringent conditions； (c) a sequence substantiallyhomologous to or that hybridizes to the sequences (a) or (b) but fordegeneracy of the genetic code； and (d) an oligonucleotide specific for any ofthe sequences (a), (b) or (c) above.
