Embryonic hematopoiesis defect in the tattered-Hokkaido (Td(ho)) mouse

Background and Purpose: The Td(ho) allele is an X-linked dominant, embryoni c 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 unti l now. The cause of lethality in Td(ho) male embryos was examined with resp ect to the defect of hematopoiesis. Methods: Suppression subtractive hybridization and Northern blot analysis w ere performed on E12.5 male Td(ho) and normal mouse embryos. In addition, h istochemical 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 Td(ho) male embryos were documented by use o f Northern blot analysis and subtractive hybridization, Increased apoptosis of yolk sac-derived erythrocytes was found in E12.5 Td(ho) male embryos. F urthermore, diminished numbers of anucleated erythrocytes were observed in E12.5 mutant embryos. Conclusions: A defect of embryonic hematopoiesis in Td(ho) mice was suggest ed as one of the possible causes of embryo lethality.