The methylation of C/EBP β gene promoter and regulated by GATA-2 protein
- 507 Downloads
Mammalian genomes are punctuated by DNA sequences containing an atypically high frequency of CpG sites (CpG islands; CGIs) that are associated with the majority of annotated gene promoters. Methylated C bases of CpG sites inhibit the expression of downstream genes. During the differentiation of 3T3-L1 preadipocytes, the CCAAT/enhancer-binding protein (C/EBP) β gene plays an important role. We studied the CpG island methylation status of the C/EBP β promoter and its relationship with the GATA-2 protein. We used computer analysis to determine that the C/EBP β promoter sequence is rich in CGIs, and observed that two of seven methylated C bases were demethylated during the preadipocyte differentiation using bisulfite sequencing PCR (BSP). This corresponded with the onset of notable C/EBP β gene expression. Immunofluorescence and molecular docking showed that the GATA-2 protein binds the C/EBP β promoter in front of the first demethylated CpG site. We also found that expression of GATA-2 and C/EBP β proteins is negatively correlated. These results indicate that the methylated C bases in the C/EBP β promoter relate to expression of the C/EBP β gene, and that its demethylation is linked with GATA-2 protein association.
KeywordsCpG island GATA-2 C/EBP β Preadipocyte Methylation
This research was supported by a grant from the Committee of Science and Technology of Shanghai, China (02DJ14005), and the “211 key program”.
- 3.Zhang N, Lin C, Huang X, Kolbanovskiy A, Hingerty BE, Amin S, Broyde S, Geacintov NE, Patel DJ (2005) Methylation of cytosine at C5 in a CpG sequence context causes a conformational switch of a benzo-pyrene diolepoxide-N2-guanine adduct in DNA from a minor groove alignment to intercalation with base displacement. J Mol Biol 346:951–965PubMedCrossRefGoogle Scholar