| Abstrakt: |
Genes of theMAGEfamily direct the expression of tumor antigens recognized on a human melanoma by autologous cytolytic T lymphocytes. Twelve closely relatedMAGEgenes are located in the Xq28 region. These genes share 60–98% nucleotide identity in their coding region. The presence of homologous genes in a region of Xp21.3 has been reported previously. We obtained the complete sequence of a 42-kb stretch of this region. It contains fourMAGE-related genes, which we propose to nameMAGE-B1, B2, B3,andB4(HGMW-approved symbols MAGEB1, MAGEB2, MAGEB3, and MAGEB4). The coding regions of these genes share 66–81% nucleotide identity and show 45–63% identity with those of theMAGEgenes located in Xq28. Like theMAGEgenes located in Xq28, theMAGE-Bgenes are silent in normal tissues with the exception of testis. LikeMAGE-1, 2, 3, 4, 6and12(HGMW-approved symbols MAGEA1, 2, 3, 4, 6, and 12), genesMAGE-B1andMAGE-B2are expressed in a significant fraction of tumors of various histological types. The transcription ofMAGE-B1andMAGE-B2can be induced by 5-aza-2′-deoxycytidine, suggesting that the activation of these genes in tumors results from a demethylation process. |
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