AimTo discover the expression of ZNF297B in the differentiation of smooth muscle cells and investigate the related mechanism.MethodsThe mRNA expression level of ZNF297B in human, rat and mouse smooth muscle cells and the change of ZNF297B expression level in smooth muscle cell differentiation and proliferation was tested by real-time PCR.The ZNF297B-Myc/His plasmid was constructed and transfected into rat smooth muscle cells to test the distribution of ZNF297B in cultured cells. The binding and interaction of ZNF297B and Myocardin was tested by luciferase assay and confirmed by co-immunoprecipitation.ResultsZNF297B was specificly highly expressed in smooth muscle cells.The expression level of ZNF297B was upregulated in the process of RA induced smooth muscle cell differentiation from mouse embryonic stem cells. ZNF297B expression was downregulated in PDGFBB stimulated smooth muscle cell proliferation process. In balloon-injured rat carotid arteries, ZNF297B was upregulated after 6 hours and then downregulated. ZNF297B mainly expressed in nucleus and the cytoplasm around nucleus. ZNF297B can bind and interact with Myocardin in protein level.ConclusionZNF297B may play an important role in smooth muscle cell differentiation.This function may be related to the interaction between ZNF297B and Myocardin.