Objective:To investigate the expression of Notch4 gene and protein in the hematopoietic system in mouse early embryos.Methods:The expression of Notch4 mRNA and protein of the Hematopoietic system form the mouse embryonic aorta-gonad-mesonephros(AGM)region and fetal liver at embryonic day(E)9.5

E10.5

E11.5

E12.5 were detected by RT-PCR and Western blot techniques.Results:In two groups of mouse early relevant hematopoietic tissue

Notch4 mRNA and protein expression of E10.5 group were significantly higher than other groups(P<0.05)in the AGM area

and decreased with the pregnancy in both the AGM and fetal liver(P<0.01).There was statistical difference at embryonic day(E)9.5 and 12.5 in the area comparison between AGM and fetal live(P<0.05).There was no statistical significance(P >0.05)at embryonic day(E)10.5 and 11.5.PT-PCR showed the same expression rules.Conclusion:The Notch4 signals are expressed in early hematopoietic tissue of mouse embryos

but its function is to be further researched.