Sperm Acrosome Biogenesis And Function During Fertilization (advances In Anatomy, Embryology And Cell Biology)
by Mariano G. Buffone /
2016 / English / PDF
3.2 MB Download
Over the last decades, acrosomal exocytosis (also called the
“acrosome reaction”) has been recognized as playing an essential
role in fertilization. Secretion of this granule is an absolute
requirement for physiological fertilization. In recent years, the
study of mammalian acrosomal exocytosis has yielded some major
advances that challenge the long-held, general paradigms in the
field. Principally, the idea that sperm must be acrosome-intact
to bind to the zona pellucida of unfertilized eggs, based largely
on in vitro fertilization studies of mouse oocytes denuded of the
cumulus oophorus, has been overturned by experiments using
state-of-the-art imaging of cumulus-intact oocytes and
fertilization experiments where eggs were reinseminated by
acrosome-reacted sperm recovered from the perivitelline space of
zygotes. From a molecular point of view, acrosome exocytosis is a
synchronized and tightly regulated process mediated by molecular
mechanisms that are homologous to those reported in
neuroendocrinal cell secretions. The authors provide a broader
perspective, focusing on a limited number of important topics
that are essential for understanding the molecular mechanisms
governing this step in the fertilization process. They also
discuss molecular aspects such as the signaling pathways leading
to exocytosis, including the participation of ion channels,
lipids, the fusion machinery proteins and the actin cytoskeleton
as well as cellular aspects such as the site of acrosomal
exocytosis and the use of gene-manipulated animals to study this
process.
Over the last decades, acrosomal exocytosis (also called the
“acrosome reaction”) has been recognized as playing an essential
role in fertilization. Secretion of this granule is an absolute
requirement for physiological fertilization. In recent years, the
study of mammalian acrosomal exocytosis has yielded some major
advances that challenge the long-held, general paradigms in the
field. Principally, the idea that sperm must be acrosome-intact
to bind to the zona pellucida of unfertilized eggs, based largely
on in vitro fertilization studies of mouse oocytes denuded of the
cumulus oophorus, has been overturned by experiments using
state-of-the-art imaging of cumulus-intact oocytes and
fertilization experiments where eggs were reinseminated by
acrosome-reacted sperm recovered from the perivitelline space of
zygotes. From a molecular point of view, acrosome exocytosis is a
synchronized and tightly regulated process mediated by molecular
mechanisms that are homologous to those reported in
neuroendocrinal cell secretions. The authors provide a broader
perspective, focusing on a limited number of important topics
that are essential for understanding the molecular mechanisms
governing this step in the fertilization process. They also
discuss molecular aspects such as the signaling pathways leading
to exocytosis, including the participation of ion channels,
lipids, the fusion machinery proteins and the actin cytoskeleton
as well as cellular aspects such as the site of acrosomal
exocytosis and the use of gene-manipulated animals to study this
process.
