The Role of Cell specific long non Coding RNAs (lncRNAs) in Stem Cells

During the first stages of development, there are two main cell types which will give rise to the embryo and to the extra-embryonic tissues; embryonic stem cells (ESCs), trophoblast stem cells (TSCs). We discovered two interesting lncRNAs that are highly expressed exclusively in TSCs. We investigated their roles by creating cell lines with knockouts of these lncRNAs, and by using methods such as transdifferentiation and reprogramming. We show that these lncRNAs are crucial for the maintenance of TSCs, and protecting them from differentiation, by inhibiting certain trophoblast differentiation genes. We discovered surprisingly that knocking out these lncRNA from ESCs led to upregulation of germ cell markers. This study sheds light on an additional layer of regulation in TSCs and the unexpected function of lncRNAs that are specific for TSCs.