My laboratory is devoted to the developmental genetic analysis of early mammalian embryos, principally the mouse. The preimplantation development of placental mammals establishes the extraembryonic cell lineages, which subsequently have protective and nutritive functions. Development of the embryonic axis and the primary germ layers occurs after implantation, during gastrulation, which establishes the body plan. We are interested in the lineage relationships during the formation of extraembryonic lineages at preimplantation stages, and during gastrulation. We find that the gastrula fate map of the mouse embryo has striking similarities with that of the chick embryo, in that all three primary germ layers (endoderm, ectoderm and mesoderm) are derived during the migration of epiblast cells into the primitive streak.
We are also attempting to identify genes involved in differentiation of these lineages. One approach is an analysis of the aberrant development of pathenogenetic and androgenetic embryos and of pluripotent embryonic stem cell derived from them. We find that the parthenogenetic embryos have major disturbances in differentiation of the extraembryonic lineages, and are currently studying the molecular basis of these defects.
A related interest is the analysis of differentiation in a laboratory marsupial, the opossum, which has major differences in developmental strategy when compared to placental mammals, especially in formation of the exraembryonic lineages.
Together, these studies exploit all current technologies, including embryo culture and cell lineage tracing, embryonic stem cell culture, transonic mice, and homologous recombination as means to a cellular and molecular understanding of mammalian development.
Lawson, K.A., Meneses, J.J., and Pedersen, R.A. (1991). Clonal analysis of epiblast fate during germ layer formation in the mouse embryo. Development. 113:891-911.
Rappolee, D.A., Sturm, K.S., Behrendtsen, O., Schultz, G.A., Pedersen, R.A., and Werb, Z. (1992). Insulin-like growth factor II acts through an endogenous pathway regulated by imprinting in early mouse embryos. Genes Dev. 6:939-952.
Latimer, J.J. and Pedersen, R.A. (1992). Epigenetic interactions and gene expression in peri-implantation mouse embryo development. In: Genes in Mammalian Reproduction, R.B.L. Gwatkin, Ed., WIley-Liss, N.Y. pp. 131-171
Burdsal, C.A., Damsky, C.H., and Pedersen, R.A. (1993). The role of E-cadherin in mesoderm differentiation and migration at the mammalian primitive streak, In Press, 1993.