Sperm-specific phospholipase C, PLCzeta, is a candidate for the Ca(2+) oscillation-inducing factor that is introduced into the ooplasm upon sperm-egg fusion. In addition to the 647-residue full-length PLCzeta, s-PLCzeta lacking the N-terminal 110 amino acids is known to be present in the mouse testis. In this study, we attempted to obtain full-term offspring from s-PLCzeta-activated eggs by rou...

During the first cell cycle Ca2+ oscillations are regulated in a cell cycle-dependent manner, such that the oscillations are unique to M phase. How the Ca2+ oscillations are regulated with such cell cycle stage-dependency is unknown, despite their importance for egg activation and embryo development. We recently identified a novel, sperm-specific phospholipase C (PLCzeta; PLCzeta) that triggers...

BACKGROUND INFORMATION At fertilization in mammalian eggs, the sperm induces a series of Ca(2+) oscillations via the production of inositol 1,4,5-trisphosphate. Increased inositol 1,4,5-trisphosphate production appears to be triggered by a sperm-derived PLCzeta (phospholipase C-zeta) that enters the egg after gamete fusion. The specific phosphatidylinositol 4,5-bisphosphate hydrolytic activity ...

It has been known for some time that mammalian eggs are activated by a series of intracellular calcium oscillations that occur shortly after sperm egg membrane fusion. Recent work has identified a novel sperm specific phospholipase C zeta as the likely agent that stimulates the calcium oscillations in eggs after sperm-egg membrane fusion. PLCzeta is stimulated by low intracellular calcium level...

Background: Failed fertilization after intracytoplasmic sperm injection (ICSI) can be due to a reduced oocyte-activation capacity caused by reduced concentrations and abnormal localization of the oocyte-activation factor phospholipase C (PLC) zeta. Patients with this condition can be helped to conceive by artificial activation of oocytes after ICSI with calcium ionophore (assisted oocyte activa...

A calcium signal during oocyte or egg activation is a conserved event in virtually all species analyzed so far. This signal, that is in the form of calcium oscillations in mammals, is spatially and temporally controlled and is mainly supported by calcium release from internal calcium stores, but how it is triggered after fertilization is far from understood. The sperm factor hypothesis of egg a...

Sperm-specific phospholipase C zeta (PLCζ) initiates intracellular calcium (Ca2+) transients which drive a series of concurrent events collectively termed oocyte activation. Numerous investigations have linked abrogation and absence/reduction PLCζ with forms male infertility in humans where activation fails. However, very few studies examined potential relationships between advancing age, both ...

Although today, there is a general consensus that egg activation involves the release of a “sperm factor” that follows gamete fusion, the identity of the molecule involves in this process is still under discussion. Recently, Asian Journal of Andrology got three successive commentary articles which target the problem of the molecular nature of the “sperm factor.” Is it PAWP, PLC zeta, or both? A...

BACKGROUND Male factor and idiopathic infertility contribute significantly to global infertility, with abnormal testicular gene expression considered to be a major cause. Certain types of male infertility are caused by failure of the sperm to activate the oocyte, a process normally regulated by calcium oscillations, thought to be induced by a sperm-specific phospholipase C, PLCzeta (PLCζ). Prev...