APax3lineage gives rise to transient haematopoietic progenitors

Abstract

During embryonic development, muscle tissues, skin, and a subset of vascular endothelial cells arise fromPax3-expressing embryonic progenitors defined as paraxial mesoderm. By contrast, haemogenic potential is well established for extra-embryonic mesoderm and intra-embryonic lateral plate mesoderm which do not expressPax3. To date, it is not known whether the haematopoietic system also containsPax3lineage cells. Here, we show that the mouse foetal liver and foetal circulation contain a transient population ofPax3lineage cells with hallmarks of haematopoietic progenitors and the potential to generate both myeloid and erythroid cells. We propose thatPax3lineage haematopoietic cells should be investigated to better understand normal haematopoietic development from different mesodermal derivatives. Further, genetic alterations ofPax3lineage haematopoietic cells should be investigated for their potential to cause haematopoietic malignancies.