In Utero Trophoblast Transgenesis

Abstract
The placenta is a unique organ that develops during pregnancy and is essential for survival and growth
of the developing fetus. A major obstacle in understanding the role of potential mediators of placental
development has been the lack of a facile method for trophoblast gene manipulation in intact animals.
Lentiviral infection of blastocysts in cell culture [ex vivo] and subsequent embryo transfer is an established
technique that leads to trophoblast gene transfer. Despite its introduction several years ago, the use of this ex
vivo embryo transfer approach to achieve trophoblast gene modulation has been limited. This is not likely due
to a lack of need for these techniques, as it provides a powerful tool to assess placental development and
dysfunction. The reasons for its limited use are likely due to the requirement for highly specialized staff, the
technically involved process, and the need to culture blastocysts in vitro to infect before embryo transfer.
To overcome the limitations of ex vivo gene transfer, we have devised and propose to validate a novel
in utero trophoblast transgenesis approach, in which nonsurgical lentiviral infection of blastocysts occurs in
utero and provides trophoblast-specific gene expression in naturally mated pregnant females. This method will
provide the ability to evaluate numerous genes in a rapid and highly efficient way to study the role of the
placenta in development and disease states. This method is straightforward, specific, does not require highly
specialized staff, and eliminates the use of anesthetic. In addition, the rate of pregnancy and pups/pregnancy
is the same naturally mated mice. Completion of the proposed aims will provide a new and powerful way to
determine the processes that regulate placentation and underlying factors involved in the development of
pregnancy-associated disorders in a highly accelerated manner.

Grant Number: 5R21HD112763-02
NIH Institute/Center: NIH
Principal Investigator: Thomas Brown