Mapping mouse gamete interaction forces reveal several oocyte membrane regions with different mechanical and adhesive properties.
This study focuses on the interaction involved in the adhesion of mouse gametes and on the mechanical properties of the oocyte membrane. The oocyte has an asymmetrical shape, and its membrane is composed of two distinct areas. One is rich in microvilli, and the other is smoother and without microvilli. With a biomembrane force probe (BFP) adapted to cell-cell measurements, we have quantified the separation forces between a spermatozoon and an oocyte. Microvillar and amicrovillar areas of the oocyte surface have been systematically probed and compared. In addition to a substantial difference in the elastic stiffness of these two regions, the experiments have revealed the presence of two types of membrane domains with different mechanical and adhesive properties, both distributed over the entire oocyte surface (i.e., in both microvillar and amicrovillar regions). If gamete contact occurs in the first type of domain, then the oocyte membrane deforms only elastically under traction. The pull-off forces in these domains are higher in the amicrovillar region. For a spermatozoon contact with the other type of domain, there can be a transition from the elastic to viscoelastic regime, and then tethers are extruded from the oocyte membrane.
Jégou
Antoine
A
Laboratoire de Physique Statistique de l'Ecole Normale Supérieure de Paris, UMR 8550 associée au CNRS et aux Universités Paris 6 et Paris 7, 24 rue Lhomond, Paris, France.
Pincet
Frédéric
F
Perez
Eric
E
Wolf
Jean Philippe
JP
Ziyyat
Ahmed
A
Gourier
Christine
C
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology; D005260:Female; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D009865:Oocytes / Q000737:chemistry* / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013090:Spermatocytes / Q000737:chemistry* / Q000502:physiology; D013314:Stress, Mechanical; D013499:Surface Properties