title: A specific flagellum beating mode for inducing fusion in mammalian fertilization and kinetics of sperm internalization.
abstract: The salient phases of fertilization are gamete adhesion, membrane fusion, and internalization of the spermatozoon into the oocyte but the precise timeline and the molecular, membrane and cell mechanisms underlying these highly dynamical events are far from being established. The high motility of the spermatozoa and the unpredictable location of sperm/egg fusion dramatically hinder the use of real time imaging optical techniques that should directly provide the dynamics of cell events. Using an approach based on microfluidics technology, the sperm/egg interaction zone was imaged with the best front view, and the timeline of the fertilization events was established with an unparalleled temporal accuracy from the onset of gamete contact to full sperm DNA decondensation. It reveals that a key element of the adhesion phase to initiate fusion is the oscillatory motion of the sperm head on the oocyte plasma membrane generated by a specific flagellum-beating mode. It also shows that the incorporation of the spermatozoon head is a two steps process that includes simultaneous diving, tilt, and plasma membrane degradation of the sperm head into the oocyte and subsequent DNA decondensation.
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ravaux
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Nabil
authors.initials: N
authors.lastname: Garroum
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Perez
authors.affiliation: Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), F-75005 Paris, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Willaime
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Gourier
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D013081:Sperm Motility / Q000502:physiology*; D013082:Sperm Tail / Q000378:metabolism*; D013084:Sperm-Ovum Interactions / Q000502:physiology*