A new study published in Cell Physiology and Biochemistry aimed to determine the spatiotemporal expression pattern of Plac1 a placenta specific gene and its exact role at the feto maternal interface. In this experiment in situ hybridization ISH was used to localize the Plac1 mRNA at the mouse feto maternal interface. Subsequently a trophoblast stem cell TS differentiation model with Plac1 shRNA overexpressing lentivirus was utilized to investigate the possible role of Plac1 in placentation. It was observed that Plac1 was exclusively expressed in the ectoplacental cone EPC as well as in 8.5 and 9.5 days post coitum dpc embryos. Henceforth Plac1 expression was abundant in the spongiotrophoblast layer and moderately in the labyrinth layer until 13.5 dpc and declined thereafter. In addition Plac1 was expressed by secondary trophoblast giant cells and glycogen trophoblast cells but not in primary trophoblast giant cells. Furthermore Plac1 transcription was increased during the TS differentiation and knockdown of Plac1 considerably impaired TS differentiation. Hence it was inferred that Plac1 is abundantly expressed at the fetomaternal interface and in all trophoblast subtypes except in primary trophoblast giant cells. The retardation of the progress of TS differentiation by Plac1 knockdown suggested that Plac1 is necessary for normal trophoblast differentiation into various trophoblast subpopulations.