Expression of two novel transcripts in the mouse definitive endoderm

Here we describe the expression of two novel transcripts, Ende (AK014119) and Npe (AK084355), during early mouse embryogenesis. Ende mRNA was first detected at embryonic day (E) 7.0 in a small population of epiblast cells in the distal half of the embryo. At E7.5, Ende was expressed by newly formed definitive endoderm cells in the proximal half of the embryo, and was not expressed in extra-embryonic endoderm. This expression pattern then changed to the ventral aspect of the developing foregut pocket and the entire hindgut pocket at E8.0-8.5, before becoming restricted to the foregut overlying the heart and the posterior-most hindgut. By E9.25 Ende expression was also observed in the posterior half of the ventral neural tube. Thus, Ende was expressed dynamically and in specific populations of the definitive endoderm from E7.0 to E8.5. We found Npe expression to be restricted to the node/posterior notochord region at the distal tip of the embryo between E7.0 and E8.0. By E9.5, Npe expression was observed in the posterior-most population of dorsal hindgut cells and notochord cells. Given their expression in mouse definitive endoderm populations, Ende and Npe will be valuable tools to study formation and development of this tissue.