Phospholipase C[zeta], the trigger of egg activation in mammals, is present in a non-mammalian species
2005
Coward, K | Ponting, C P | Chang, H. Y. | Hibbitt, O | Savolainen, P | Jones, K T | Parrington, J
The activation of the egg to begin development into an embryo is triggered by a sperm-induced increase in intracellular egg Ca²⁺. There has been much controversy about how the sperm induces this fundamental developmental event, but recent studies suggest that, in mammals, egg activation is triggered by a testis-specific phospholipase C: PLC[zeta]. Since the discovery of PLC[zeta], it has been unclear whether its role in triggering egg activation is common to all vertebrates, or is confined to mammals. Here, we demonstrate for the first time that PLC[zeta] is present in a non-mammalian vertebrate. Using genomic and cDNA databases, we have identified the cDNA encoding a PLC[zeta] orthologue in the domestic chicken that, like the mammalian isoforms, is a testis-specific gene. The chicken PLC[zeta] cDNA is 2152 bp in size and encodes an open reading frame of 639 amino acids. When injected into mouse oocytes, chicken PLC[zeta] cRNA triggers Ca²⁺ oscillations, indicating that it has functional properties similar to those of mammalian PLC[zeta]. Our findings suggest that PLC[zeta] may have a universal role in triggering egg activation in vertebrates.
显示更多 [+] 显示较少 [-]