Transcription Factor FOXM1 Inhibits The DNase Activity Of Nuclease DIS3 And Its Biological Function

Forkhead box M1(FOXM1)is a member of the FOX transcription factor family and is closely related to a variety of cellular biological effects,such as: proliferation,DNA damage repair,apoptosis and redox signaling.In addition to being beneficial to the normal function of cells,FOXM1 is highly expressed in a variety of cancers,can promote tumor cell growth,invasion and metastasis,etc.,and is also associated with poor prognosis.FOXM1,as a DNA-binding protein of transcription factors,is mainly located in the nucleus and plays the function of regulating gene expression.In order to further expand the understanding of the function of FOXM1 protein,we used the pulldown results of FOXM1 to perform mass spectrometry identification and found a potential FOXM1-interacting protein DIS3(exosome complex exonuclease Rrp44).DIS3 is a member of the catalytic subunit of the exosome complex,with 3’-5’exonuclease and endonuclease activities,mainly located in the nucleus,and involved in the processing and degradation of various types of nucleic acids.DIS3 mutations or loss of expression are present in a variety of clinical tumors.Therefore,we speculate that the binding of FOXM1 to DIS3 may be related to the loss of DNA.This paper carried out related work from the following four aspects.First,the interaction between FOXM1 and DIS3 protein was confirmed.Using the methods of bimolecular fluorescence complementation,cell immunofluorescence staining,protein co-immunoprecipitation and pulldown,it was confirmed that the transcription factor FOXM1 can interact with the nuclease DIS3 protein.Secondly,it was proved that DIS3 has DNase activity;eukaryotic and prokaryotic DIS3 proteins were purified by GFP-Trap and His-pulldown methods,and the protein DIS3 was proved to have DNA nuclease activity under different conditions of temperature,p H and ion.Again,it was proved that FOXM1 can inhibit the DNase activity of DIS3 protein.Nucleic acid degradation experiments were performed using eukaryotic and prokaryotic expression of FOXM1 protein and prokaryotic expression of DIS3 protein,which proved that FOXM1 protein can inhibit the ability of DIS3 to degrade DNA.Finally,using cell immunofluorescence and Western blotting methods to prove that DIS3 protein can enhance the DNA damage repair response.The possible function of FOXM1 involved in repairing DNA loss through DIS3 was explored by Western blotting.In conclusion,the experimental results in this paper show that the transcription factor FOXM1 can interact with the nuclease DIS3 protein.The nuclease DIS3 has DNA-degrading activity.The interaction of FOXM1 and DIS3 protein is not conducive to DNA loss repair.The results of this paper provide a new direction for expanding the molecular function of transcription factor FOXM1 in the nucleus.