Abstract: Objective To observe changes of cell cycle regulators after down-regulation of GINS2 in HL60 cells lines and investigate related mechanism. Methods The recombinant plasmid carrying siRNA and non-homologous sequence were stably transfected into HL60 cells as experimental group and negative control group respectively, while, blank control group only treated by lipidosome and HL60 cells acted as untreated group. Flow cytometry was used to detect the cell cycle of HL60，3H-TdR incorporation assay and Colony-forming test were performed to measure duplication and nucleic acid synthesis in four groups either. The protein expression of cycle regulatory proteins CDK1 and CyclinB1 were measured by Western blot. Meanwhile，transcription and translation levels of ATM，CHK2,P53 were detected by RT-PCR and Western blot respectively. Results 48h after transfection, GFP could be observed by Fluorescence microscope. Flow cytometry showed that cell growth was significantly inhibited and G2 peak was found in interfering group. Compared with other three groups，nucleic acid synthesis and cell proliferation was blocked in experimental group. CDK1，cyclinB1 related with cell cycle regulation were dramatically decreased over time. Together，both RT-PCR and Western blot demonstrated that the transcription and translation levels of ATM，CHK2,P53 were notably increased. Conclusions Down-regulation of GINS2 can suppress nucleic acid duplication and influence cell cycle process of HL60 by up-regulation of ATM，CHK2 and P53.

Key words: GINS2 gene, HL60 cell, G2 arrest, leukemia