The placenta is a transient organ that plays a critical role in sustaining pregnancy and supporting fetal growth and nutrition. The placental epithelium is comprised of trophoblast cells. Trophoblast cells are the first cell type to differentiate during embryogenesis and ultimately diversify into a heterogeneous population of cells specializing in distinct functions essential for placentation. The emergence of the trophoblast lineage and subsequent specialization into distinct trophoblast sublineages is tightly regulated by transcription factors. This chapter will provide an overview of transcription factors that regulate trophoblast development and function. The chapter is divided into three sections. In the first section, a generalized outline of trophoblast ontogeny and a functional description of different trophoblast sublineages will be provided. In the second section, transcription factors involved in emergence of the trophoblast lineage and maintenance of trophoblast stem cells will be discussed. In the third section, transcription factors implicated in the formation and function of villous and extravillous cytotrophoblast lineages will be described.
Understanding cell fate patterning and morphogenesis in the mammalian embryo remains a formidable challenge. Recently, in vivo models based on embryonic stem cells (ESCs) have emerged as complementary methods to quantitatively dissect the physical and molecular processes that shape the embryo. Here we review recent developments in using ESCs to create both two- and three-dimensional culture models that shed light on mammalian gastrulation.