Cyclic QDE peptide increases fertilization rates and provides healthy pups in mouse.

Objective: To evaluate the effects of cyclic QDE peptide (cQDE), derived from sperm fertilin beta (ADAM2), in mouse in vitro fertilization (IVF) and its harmlessness on pups after embryo transfer.

Design: Prospective in vivo and in vitro study in mice.

Setting: Murine model in an academic research environment in France.

Alpha6beta1 integrin expressed by sperm is determinant in mouse fertilization.

Background: Based on inhibition tests, the alpha6beta1 integrin was suggested to be a sperm receptor, but further experiments using gene deletion techniques have shown that neither oocyte alpha6, nor beta1 integrin subunits were essential for mouse fertilization.

Results: Using Western blot analysis and immunofluorescence, we showed that the mouse sperm expresses the alpha6beta1 integrin. As for oocyte, binding of GoH3 anti-alpha6 antibody to sperm induces a specific inhibition of sperm fertilizing ability.

Transfer of oocyte membrane fragments to fertilizing spermatozoa.

Several families of molecules are implicated in the membrane fusion process between sperm and oocyte. Among these, CD9 tetraspanin, a membrane-organizing molecule, plays a crucial role, since the fertilizing ability of CD9-/- oocytes is dramatically impaired. CD9 controls alpha6-beta1 integrin relocation involved in the membrane reorganization that occurs on oocyte fertilization but is not expressed on sperm.