What triggers Acrosomal reaction?
Zona pellucida is the natural inducer of the acrosome reaction. Binding of the sperm receptor to ZP3, a zona glycoprotein acting as ligand, triggers the molecular events leading to acrosomal exocytosis.
What is the function of Zona lysin?
It has been hypothesized that the penetration of the mammalian VC, the zona pellucida (ZP), is aided by a proteolytic enzyme capable of locally degrading ZP proteins. This putative “zona lysin” is predicted to reside within the sperm head acrosome and be released or exposed by ZP-induced acrosomal exocytosis.
What does acrosome defect mean?
It is characterized by abnormal sperm and leads to an inability to father biological children (infertility). Normal sperm cells have an oval-shaped head with a cap-like covering called the acrosome. The acrosome contains enzymes that break down the outer membrane of an egg cell, allowing the sperm to fertilize the egg.
What happens during an acrosomal reaction?
The acrosome reaction allows the sperm by exocytotic release of acrosomal enzymes to penetrate the zona pellucida of the egg. The species-specific zona pellucida protein that serves as a sperm receptor also stimulates a series of events that lead to fusion between the plasma membrane and outer acrosomal membrane.
What is acrosomal reaction in zoology?
During fertilization, a sperm must first fuse with the plasma membrane and then penetrate the female egg cell to fertilize it. Therefore, sperm cells go through a process known as the acrosome reaction, which is the reaction that occurs in the acrosome of the sperm as it approaches the egg.
What is zona pellucida 12?
Zona pellucida is the thick transparent membrane and it is surrounded by the mammalian ovum before implantation. It prevents polyspermy. Acrosome reaction is enabled by zona pellucida to produce the comfortness for the sperm.
What happens if zona pellucida ruptures early?
Early in the second week of gestation, the zona pellucida ruptures and the blastocyst is freed or hatched (Figure 1(g)). Cell division continues and, since the blastocyst is no longer confined within the zona, it can now increase in size.
What will happen if the acrosome of a sperm is removed?
Sperm that are unable to go through the acrosome reaction properly will not be able to fertilize an egg.