Connexins and trophoblast cell lineage development.

The mouse is a valuable model for studying basic mechanisms of gene regulation in trophoblast cell lineage differentiation. Elements of placental development are conserved across species, including trophoblast proliferation, differentiation, migration, and vessel invasion. Among the regulatory processes, direct intercellular communication between trophoblast cells via gap junction channels seems to play a crucial role in placental development and physiology. Here we describe in detail the generation of trophoblast stem (TS) cell lines from connexin-deficient mice. The design of differentiation and proliferation assays are specified including marker gene sets which are important for analyzing and comparing the differentiation capacity of the connexin-deficient TS cell lines. Furthermore, we show that TS cells are capable of forming tumors after subcutaneous injection into nude mice, providing the opportunity to investigate trophoblast invasion into host vessels in vivo.