Embryonic hematopoiesis defect in the tattered-Hokkaido (Tdho) mouse.

BACKGROUND AND PURPOSE: The Tdho allele is an X-linked dominant, embryonic male-lethal mouse mutation that occurs between embryonic day (E) 12.5 and E14.5. The lethal cause and responsible gene have not been identified until now. The cause of lethality in Tdho male embryos was examined with respect to the defect of hematopoiesis. METHODS: Suppression subtractive hybridization and Northern blot analysis were performed on E12.5 male Tdho and normal mouse embryos. In addition, histochemical examinations and blood cell counts of normal and mutant E12.5 embryos were carried out. RESULTS: Diminished expression of embryonic globin genes (zeta and epsilon globins) in the blood of E12.5 Tdho male embryos were documented by use of Northern blot analysis and subtractive hybridization. Increased apoptosis of yolk sac-derived erythrocytes was found in E12.5 Tdho male embryos. Furthermore, diminished numbers of anucleated erythrocytes were observed in E12.5 mutant embryos. CONCLUSIONS: A defect of embryonic hematopoiesis in Tdho mice was suggested as one of the possible causes of embryo lethality.