LINE1-Type Transposase Domain Containing Protein 1 (L1TD1)

L1TD1 is a marker for undifferentiated human embryonic stem cells. L1TD1 is abundantly expressed in undifferentiated hESC. Differentiation of hESC via embryoid body (EB) formation or BMP4 treatment results in the rapid down-regulation of L1TD1 expression. L1TD1 is enriched in the SSEA4-positive or TRA160-positive population of hESC. Furthermore, siRNA-mediated knockdown of Nanog in hESC also resulted in downregulation of L1TD1 expression. Finally, using luciferase reporter assay we demonstrated that Nanog can activate the L1TD1 upstream promoter region. Altogether, these results provide evidence that L1TD1 is a downstream target of Nanog. L1TD1 is a downstream target of Nanog and represents a useful marker for identifying undifferentiated hESC.