Methyl-CpG binding domain proteins and their involvement in the regulation of the MAGE-A1, MAGE-A2, MAGE-A3, and MAGE-A12 gene promoters.
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Methyl-CpG binding domain proteins and their involvement in the regulation of the MAGE-A1, MAGE-A2, MAGE-A3, and MAGE-A12 gene promoters. / Wischnewski, Frank; Friese, Olaf; Pantel, Klaus; Schwarzenbach, Heidi.
In: MOL CANCER RES, Vol. 5, No. 7, 7, 2007, p. 749-759.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Methyl-CpG binding domain proteins and their involvement in the regulation of the MAGE-A1, MAGE-A2, MAGE-A3, and MAGE-A12 gene promoters.
AU - Wischnewski, Frank
AU - Friese, Olaf
AU - Pantel, Klaus
AU - Schwarzenbach, Heidi
PY - 2007
Y1 - 2007
N2 - Promoter hypermethylation is responsible for the restricted expression of the tumor-associated MAGE antigens. In order to elucidate the mechanism underlying methylation-dependent repression, we examined the involvement of methyl-CpG binding proteins, MBD1, MBD2a, and MeCP2, in silencing of MAGE-A1, MAGE-A2, MAGE-A3, and MAGE-A12 genes. Electrophoretic mobility shift assays displayed binding of MBD1 to the methylated and unmethylated MAGE-A promoters. Using chromatin immunoprecipitation assays, in vivo binding of MBD1 and MeCP2 to the promoters could be observed in MCF-7 and T47D cells. Transient transfection assays of MCF-7 cells were done with the transcriptional repression domains (TRD) of MBD1, MBD2a, and MeCP2, and MAGE-A1, MAGE-A2, MAGE-A3, and MAGE-A12 promoters. Whereas the TRD of MBD1 and MeCP2 repressed the MAGE-A promoters, the TRD of MBD2 had no inhibiting effect on the promoter activity. Furthermore, cotransfections of Mbd1-deficient mouse fibroblasts and MCF-7 cells with MBD2a, MeCP2, and the MBD1 splice variants, 1v1 and 1v3, showed that strong methylation-dependent repression of the MAGE-A promoters could not be further down-regulated by these proteins. However, the two MBD1 splice variants, 1v1 and 1v3, were able to repress the basal activity of unmethylated MAGE-A promoters. Additional cotransfection experiments with both isoforms of MBD1 and the transcription factor Ets-1 showed that Ets-1 could not abrogate the MBD1-mediated suppression. In contrast with the repressive effect mediated by MBD1, MBD2a was found to up-regulate the basal activity of the promoters. In conclusion, these data show, for the first time, the involvement of methyl-CpG binding domain proteins in the regulation of the MAGE-A genes.
AB - Promoter hypermethylation is responsible for the restricted expression of the tumor-associated MAGE antigens. In order to elucidate the mechanism underlying methylation-dependent repression, we examined the involvement of methyl-CpG binding proteins, MBD1, MBD2a, and MeCP2, in silencing of MAGE-A1, MAGE-A2, MAGE-A3, and MAGE-A12 genes. Electrophoretic mobility shift assays displayed binding of MBD1 to the methylated and unmethylated MAGE-A promoters. Using chromatin immunoprecipitation assays, in vivo binding of MBD1 and MeCP2 to the promoters could be observed in MCF-7 and T47D cells. Transient transfection assays of MCF-7 cells were done with the transcriptional repression domains (TRD) of MBD1, MBD2a, and MeCP2, and MAGE-A1, MAGE-A2, MAGE-A3, and MAGE-A12 promoters. Whereas the TRD of MBD1 and MeCP2 repressed the MAGE-A promoters, the TRD of MBD2 had no inhibiting effect on the promoter activity. Furthermore, cotransfections of Mbd1-deficient mouse fibroblasts and MCF-7 cells with MBD2a, MeCP2, and the MBD1 splice variants, 1v1 and 1v3, showed that strong methylation-dependent repression of the MAGE-A promoters could not be further down-regulated by these proteins. However, the two MBD1 splice variants, 1v1 and 1v3, were able to repress the basal activity of unmethylated MAGE-A promoters. Additional cotransfection experiments with both isoforms of MBD1 and the transcription factor Ets-1 showed that Ets-1 could not abrogate the MBD1-mediated suppression. In contrast with the repressive effect mediated by MBD1, MBD2a was found to up-regulate the basal activity of the promoters. In conclusion, these data show, for the first time, the involvement of methyl-CpG binding domain proteins in the regulation of the MAGE-A genes.
M3 - SCORING: Zeitschriftenaufsatz
VL - 5
SP - 749
EP - 759
JO - MOL CANCER RES
JF - MOL CANCER RES
SN - 1541-7786
IS - 7
M1 - 7
ER -