Objective:To investigate expression and role of nesprins gene during mouse embryonic stem cell(ESC)differentiation into cardiomyocyte in vitro.Methods:Mouse ESC cultrued in combining 5-azacytidine as inducer with hanging drop cultures and the differentiated cells were identified with cardiac special genes and proteins;The mRNA expression of nesprin-1 and nesprin-2 genes were detected by reverse transcription-polymerase chain reaction(RT-PCR)

and sub-cellular location of nesprin-1 protein in nucleus was detected by immunofluorescence in d7

d7+3

d7+6

d7+9 and d7+20.Results:The expression of nesprin-1 and nesprin-2 genes mRNA can be found in the period of mouse ESC differentiation into cardiomyocyte.There is expression peak of nesprin-1 gene mRNA in d7

d7+3

d7+6

then declined gradually to the lowest in d7+20;expression peak of nesprin-2 gene mRNA in d7

then also declined gradually to the lowest in d7+20;The protein of nesprin-1 can be detected in the period of mouse ESC differentiation into cardiomyocyte

and mainly located in nuclear envelope and space around nuclei.Conclusion:The expression peak of nesprin-1 and nesprin-2 gene mRNA is interrelated with the phase of inducing and specialization of ESC differentiation into cardiac muscle cell

it can be speculated that nesprin genes has an important role in maintaining ESC differentiation into cardiac muscle cell.