Human gamete fusion can bypass 1 integrin requirement
Source: Human Reproduction, Volume 13, Number 3, March 1998 , pp. 682-689(8)
Publisher: Oxford University Press
Abstract:Since 61 integrin has been shown to function as a sperm adhesion receptor in the mouse, we investigated the potential role of 1 integrin in the gamete fusion process in humans. The expression of 1 integrin was morphologically analysed by indirect immunofluorescence and confocal microscopy. A homogeneous and intense staining was detected at the plasma membrane, and in some subcortical vesicles of germinal vesicle stage oocytes (GV). 1 almost disappeared from oolemma and cytoplasm of metaphase I (MI) oocytes, but was re-expressed as asymmetrical patches at the plasma membrane of metaphase II stage oocytes (MII). A functional fusion assay based on Hoechst or calcein-AM dye transfer from one gamete to the other showed that maturing oocytes were able to fuse with an increasing number of spermatozoa (11-22 from GV to MII respectively), and that fused spermatozoa co-localized with 1 integrin patches. Human gamete fusion was only partially inhibited either by RGD-containing peptide (GRGDTP), or by blocking anti-human 1 integrin monoclonal antibody (DE9), with a maximum of 50% inhibition. Despite the combined addition of GRGDTP and blocking mouse anti-human 1 integrin DE9 in the assay, a complete inhibition of fusion could not be achieved. A mouse polyclonal antibody raised against human oocyte membranes was more potent in inhibiting the fusion. Since 1 integrin expression at the plasma membrane was not correlated to oocyte fusibility, and since it was only partially inhibited by DE9 and/or RGD peptide, we suggest that human gamete fusion can bypass the 1 requirement. 1 integrin certainly participates in human gamete fusion by acting in co-operation with multiple integrin/disintegrin couples or another cofactor, not yet identified.Keywords:1 integrin/human gamete fusion
Document Type: Research article
Affiliations: 1: Laboratoire de Biologie de la Reproduction, Hopital Cochin, 123 Boulevard Port Royal, 75014 Paris, France 2: Laboratoire de Biologie de la Reproduction, Faculte de Medecine de Bobigny, 74 Rue Marcel Cachin, 93017 Bobigny, France 3: Institut Cochin de Genetique Moleculaire, U322, 22 Rue Mechain, 75014 Paris, France
Publication date: 1998-03-01
- Human Reproduction features full-length, peer-reviewed papers reporting original research, clinical case histories, as well as opinions and debates on topical issues. Papers published cover the scientific and medical aspects of reproductive physiology and pathology, endocrinology, andrology, gonad function, gametogenesis, fertilization, embryo development, implantation, pregnancy, genetics, genetic diagnosis, oncology, infectious disease, surgery, contraception, infertility treatment, psychology, ethics and social issues. The highest scientific and editorial standard is maintained throughout the journal along with a rapid rate of publication.