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Methylated CpG points identified within MAGE‐1 promoter are involved in gene repression
Author(s) -
Serrano Alfonso,
García Angel,
Abril Eduardo,
Garrido Federico,
RuizCabello Francisco
Publication year - 1996
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19961115)68:4<464::aid-ijc11>3.0.co;2-5
Subject(s) - demethylating agent , methylation , microbiology and biotechnology , dna methylation , cpg site , biology , gene , gene expression , promoter , cancer research , genetics
The MAGE‐1 gene, expressed in some tumors of different histological origins, codes for a tumor antigen recognized by cytotoxic T lymphocytes. The gene is not expressed in normal tissues with the exception of testes. The present study was designed to investigate the relationship between methylation of the MAGE‐1 promoter and inactivation of the MAGE‐1 gene. We examined the extent to which MAGE‐1 B′B promoter sequences are methylated in tumor‐cell lines, in order to determine whether methylation correlates with MAGE‐1 expression. Using methylation‐sensitive restriction analysis followed by polymerase chain reaction (PCR), we found an inverse correlation between methylation of the MAGE‐1 B′B region and MAGE‐1 expression. An unmethylated state was identified in DNA from sperm and some tumor‐cell lines of different origins. In contrast, a hypermethylation state was found in leukocytes and other MAGE‐1 non‐expressing cells. Furthermore, treatment with 5‐aza‐2′‐deoxycytidine, a demethylating agent, induced MAGE‐1 expression in tumor‐cell lines in which we found no direct relation between transcriptional activity of the B′B region and MAGE‐1 expression. Binding of the nuclear factors to the B′‐methylated probe was strongly inhibited, indicating that methylation of cytosine interferes directly in the binding of transcriptional factors. © 1996 Wiley‐Liss, Inc.