Kobayashi, MichihiroShelley, W. ChristopherSeo, WooseokVemula, SasidharLin, YangLiu, YanKapur, ReubenTaniuchi, IchiroYoshimoto, Momoko2016-02-292016-02-292014-08-19Kobayashi, M., Shelley, W. C., Seo, W., Vemula, S., Lin, Y., Liu, Y., … Yoshimoto, M. (2014). Functional B-1 progenitor cells are present in the hematopoietic stem cell-deficient embryo and depend on Cbfβ for their development. Proceedings of the National Academy of Sciences of the United States of America, 111(33), 12151–12156. http://doi.org/10.1073/pnas.1407370111https://hdl.handle.net/1805/8551The fetal liver is a major hematopoietic site containing progenitor cells that give rise to nearly all blood cells, including B-1 cells. Because the fetal liver is not a de novo site of hematopoietic stem cell (HSC) or progenitor-cell emergence, it must be seeded by yolk sac (YS)-derived erythromyeloid progenitors at embryonic day (E) 8.5-E10 and aorta-gonado-mesonephros (AGM)-derived HSCs at E10.5-E11.5. Although the B-1 progenitor cell pool in the fetal liver is considered to be of HSC origin, we have previously proposed that YS-derived B-1 progenitors may also contribute to this pool. Until now, it has been impossible to determine whether HSC-independent B-1 progenitor cells exist in the fetal liver. Here, we demonstrate the presence of transplantable fetal-liver B-1 and marginal zone B progenitor cells in genetically engineered HSC-deficient embryos. HSC-deficient YS and AGM tissues produce B-1 progenitors in vitro and thus may serve as sites of origin for the B-1 progenitors that seed the fetal liver. Furthermore, we have found that core-binding factor beta (Cbfβ) expression is required for fetal-liver B-1 progenitor cell maturation and expansion. Our data provide, to our knowledge, the first evidence for the presence of B-1 progenitor cells in the fetal liver that arise independently of HSCs and implicate Cbfβ as a critical molecule in the development of this lineage.en-USIUPUI Open Access PolicyTEKHemogenic endothelial cellImmune layered modeArticle