title: The p53-inducible gene 3 (PIG3) contributes to early cellular response to DNA damage.
abstract: The p53-inducible gene 3 (PIG3) is originally isolated as a p53 downstream target gene, but its function remains unknown. Here, we report a role of PIG3 in the activation of DNA damage checkpoints, after UV irradiation or radiomimetic drug neocarzinostatin (NCS). We show that depletion of endogenous PIG3 sensitizes cells to DNA damage agents, and impaired DNA repair. PIG3 depletion also allows for UV- and NCS-resistant DNA synthesis and permits cells to progress into mitosis, indicating that PIG3 knockdown can suppress intra-S phase and G2/M checkpoints. PIG3-depleted cells show reduced Chk1 and Chk2 phosphorylation after DNA damage, which may directly contribute to checkpoint bypass. PIG3 exhibited diffuse nuclear staining in the majority of untreated cells and forms discrete nuclear foci in response to DNA damage. PIG3 colocalizes with gamma-H2AX and 53BP1 to sites of DNA damage after DNA damage, and binds to a gamma-H2AX. Notably, PIG3 depletion decreases the efficient induction and maintenance of H2AX phosphorylation after DNA damage. Moreover, PIG3 contributes to the recruitment of 53BP1, Mre11, Rad50 and Nbs1 to the sites of DNA break lesions in response to DNA damage. Our combined results suggest that PIG3 is a critical component of the DNA damage response pathway and has a direct role in the transmission of the DNA damage signal from damaged DNA to the intra-S and G2/M checkpoint machinery in human cells.
authors.affiliation: Department of Bio-materials, DNA Repair Research Center, Chosun University, Gwangju, Chonnam 501-759, Republic of Korea.
authors.forename: J-H
authors.initials: JH
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Kang
authors.forename: V
authors.initials: V
authors.lastname: Khare
authors.forename: Z-Y
authors.initials: ZY
authors.lastname: Jin
authors.forename: M-Y
authors.initials: MY
authors.lastname: Kang
authors.forename: Y
authors.initials: Y
authors.lastname: Yoon
authors.forename: J-W
authors.initials: JW
authors.lastname: Hyun
authors.forename: M-H
authors.initials: MH
authors.lastname: Chung
authors.forename: S-I
authors.initials: SI
authors.lastname: Cho
authors.forename: J Y
authors.initials: JY
authors.lastname: Jun
authors.forename: I-Y
authors.initials: IY
authors.lastname: Chang
authors.forename: H J
authors.initials: HJ
authors.lastname: You
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D005434:Flow Cytometry; D045325:HCT116 Cells; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D000071857:Tumor Suppressor p53-Binding Protein 1; D014466:Ultraviolet Rays; D009353:Zinostatin / Q000494:pharmacology
chemical_list: D000903:Antibiotics, Antineoplastic; C468783:H2AX protein, human; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; C498301:TP53BP1 protein, human; C411296:TP53I3 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; D009353:Zinostatin; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C000605867:CHEK1 protein, human; C578634:CHEK2 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases