Biochemistry and Cell Biology of Reproduction

Gametogenesis, Epididymal Maturation, Fertilization, and Preimplantation Embryo Development

UNIVERSITY OF PENNSYLVANIA | PERELMAN SCHOOL OF MEDICINE

Laboratory of George L. Gerton, Ph.D.


The Gerton laboratory uses a multidisciplinary approach to examine issues pertaining to mammalian spermatogenesis, sperm function, fertilization, and preimplantation embryo development.

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Several of the major components of the acrosome and sperm tail have been purified and their corresponding cDNAs cloned for studies of protein structure and expression. The deduced amino acid sequences of these proteins have provided new clues concerning the functions of acrosomal and flagellar proteins. One major direction of the laboratory is to study acrosomal and flagellar protein targeting and function in spermatogenic cells and transfected somatic cells using tools of molecular biology and cell biology and to extend these studies to cases of infertility in humans and other species.

Other projects in the laboratory focus upon the functions of proteins identified as components of the sperm acrosome. Acrosomal matrix protein sp56 is involved in sperm-zona pellucida interactions. These studies are leading to a re-evaluation of acrosomal exocytosis. A revised paradigm has been developed that describes acrosomal exocytosis as a continuously variable process with functional intermediates rather a two-step, acrosome-intact/acrosome-reacted process.

We are also continuing our analysis of the roles of proteins associated with the accessory structures of sperm flagellum. These non-axonemal proteins perform novel functions in regulating sperm motility.

Regarding preimplantation embryo development in mammals, we are studying the function of progranulin, the precursor of the granulin and epithelin peptides, on mouse embryos. Our results show that acrogranin is an essential growth factor for the development of embryos to the blastocyst stage.