AIM:pUL23,the product of human cytomegalovirus (HCMV) gene UL23 was identified as one of tegument proteins. The aim of this research is to investigate the function of pUL23 during HCMV life cycle.METHODS:GAL4 yeast two-hybrid assay was performed to screen the human fetal kidney cDNA library to obtain host cell protein molecules which interact with pUL23 of HCMV. Then the GST-pulldown experiment was applied to confirm the protein interactions identified by yeast two-hybrid.RESULTS:ATPase inhibitory factor 1 (ATIF1) was selected from host cells using yeast two-hybrid assay. GST-pulldown experiments in vitro further confirmed the interaction between ATIF1 and pUL23.CONCLUSION:pUL23 of HCMV can interact with ATIF1 in host cell,which may provide the evidence for understanding the function of pUL23 in the life cycle of HCMV.