Submitted May 23, 2007
Accepted January 14, 2008
Runx1 is involved in primitive erythropoiesis in the mouse
Tomomasa Yokomizo, Kazuteru Hasegawa, Hiroyuki Ishitobi, Motomi Osato, Masatsugu Ema, Yoshiaki Ito, Masayuki Yamamoto, and Satoru Takahashi*
Department of Anatomy and Embryology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Japan
Institute of Molecular and Cell Biology and Oncology Research Institute, Singapore, Singapore
Department of Molecular and Developmental Biology, Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Japan
Laboratory Animal Resource Center, University of Tsukuba, Tsukuba, Japan
* Corresponding author; email: satoruta{at}md.tsukuba.ac.jp.
Targeted disruption of the Runx1/ AML1 gene in mice has demonstrated that it is required for the emergence of definitive hematopoietic cells, but that it is not essential for the formation of primitive erythrocytes. These findings led to the conclusion that Runx1 is a stage-specific transcription factor acting only during definitive hematopoiesis. However, the zebrafish and Xenopus homologues of Runx1 have been shown to play roles in primitive hematopoiesis, suggesting that mouse Runx1 might also be involved in the development of primitive lineages. In this study, we show that primitive erythrocytes in Runx1-/- mice display abnormal morphology and reduced expression of Ter119, Erythroid Kruppel-like factor (EKLF, KLF1), and GATA-1. These results suggest that mouse Runx1 plays a role in the development of both primitive and definitive hematopoietic cells.
