Transcription factors Oct-1 and NF-YA regulate the p53-independent induction of the GADD45 following DNA damage.
The p53-regulated GADD45 gene is one of the important players in cellular response to DNA damage, and probably involved in the control of cell cycle checkpoint, apoptosis and DNA repair. There are both the p53-dependent and -independent pathways that regulate GADD45 induction. Following ionizing radiation, induction of the GADD45 gene is regulated by p53 through the p53-binding motif located in the third intron of the GADD45 gene. In contrast, GADD45 induction by methyl methanesulfonate (MMS), UV radiation (UV), and medium starvation is independent of p53 status although p53 may contribute to these responses. However, the regulatory elements that control the p53-independent induction of GADD45 remain uncertain. In this report, we have performed detailed analyses to characterize the responsive components that are required for the induction of the GADD45 promoter. We have found that the region between -107 and -62 of the GADD45 promoter is crucial for the induction. Sequence analysis indicates that there are two OCT-1 sites and one CAAT box located in this region. Site-directed mutations of both OCT-1 and CAAT motifs substantially abrogate the induction of the GADD45 promoter by DNA damage. In addition, both Oct-1 protein (binding to OCT-1 site) and NF-YA protein (binding to CAAT box) are induced after cell exposure to DNA damaging agents. Moreover, the Electrophoretic Mobility Shift Assay (EMSA) has demonstrated the direct bindings of Oct-1 and NF-YA proteins to their consensus sequences in the GADD45 promoter. Therefore, these results have presented the novel observation that transcription factors Oct-1 and NF-YA participate in the cellular response to DNA damage and are involved in the regulation of stress-inducible genes.
Jin
S
S
Department of Radiation Oncology, Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, PA 15213, USA.
Fan
F
F
Fan
W
W
Zhao
H
H
Tong
T
T
Blanck
P
P
Alomo
I
I
Rajasekaran
B
B
Zhan
Q
Q
D001483:Base Sequence; D001665:Binding Sites; D023081:CCAAT-Binding Factor / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism; D016384:Consensus Sequence; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D005809:Genes, Regulator; D051863:Host Cell Factor C1; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008741:Methyl Methanesulfonate; D008969:Molecular Sequence Data; D009153:Mutagens; D050811:Octamer Transcription Factor-1; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000096:biosynthesis / Q000502:physiology*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism / Q000502:physiology*; D014466:Ultraviolet Rays; D000097642:GADD45 Proteins
D023081:CCAAT-Binding Factor; D004268:DNA-Binding Proteins; D051863:Host Cell Factor C1; D047908:Intracellular Signaling Peptides and Proteins; D008741:Methyl Methanesulfonate; D009153:Mutagens; D050811:Octamer Transcription Factor-1; D011506:Proteins; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D000097642:GADD45 Proteins; C497692:HCFC1 protein, human; C492061:NFYA protein, human; C494165:POU2F1 protein, human