Hematopoietic stem cells, hematopoiesis and disease: lessons from the zebrafish model.

The zebrafish model is rapidly gaining prominence in the study of development, hematopoiesis, and disease. The zebrafish provides distinct advantages over other vertebrate models during early embryonic development by producing transparent, externally fertilized embryos. Embryonic zebrafish are easily visualized and manipulated through microinjection, chemical treatment, and mutagenesis.

Bef medaka mutant reveals the essential role of c-myb in both primitive and definitive hematopoiesis.

Vertebrate hematopoiesis is characterized by two evolutionally conserved phases of development, i.e., primitive hematopoiesis, which is a transient phenomenon in the early embryo, and definitive hematopoiesis, which takes place in the later stages.

GFP transgenic mice reveal active canonical Wnt signal in neonatal brain and in adult liver and spleen.

In the past decades, the function of the Wnt canonical pathway during embryogenesis has been intensively investigated; however, little survey of neonatal and adult tissues has been made, and the role of this pathway remains largely unknown. To investigate its role in mature tissues, we generated two new reporter transgenic mouse lines, ins-TOPEGFP and ins-TOPGAL, that drive EGFP and beta-galactosidase expression under TCF/beta-catenin, respectively. To obtain the accurate expression pattern, we flanked these transgenes with the HS4 insulator to reduce chromosomal positional effects.