Alternative titles; symbols
HGNC Approved Gene Symbol: MAGEB1
Cytogenetic location: Xp21.2 Genomic coordinates (GRCh38): X:30,243,731-30,252,040 (from NCBI)
By cDNA selection, Dabovic et al. (1995) isolated 2 new genes from the DSS (300018) critical region. These genes, called DAM6 (MAGEB2; 300098) and DAM10 (for 'DSS/AHC critical interval genes, belonging to the MAGE superfamily'), are expressed in adult testis and lung tumors, are 82% identical, and belong to a family of genes clustered within 50 kb of Xp21.
By means of exon-trapping of cosmids in the Xp21.3 region, Muscatelli et al. (1995) isolated a gene with strong homology to the MAGE gene family (see MAGEA1; 300016) located in Xq28. The gene is expressed only in testis and, unlike the Xq28 MAGE genes, it was not expressed in any of the 12 different tumor tissues tested. However, the gene and predicted protein structure are conserved, suggesting a function similar to that of the other MAGE genes.
Muscatelli et al. (1995) found that the MAGEB1 gene contains 4 exons. Through analysis of the sequence of cDNA and genomic clones corresponding to this gene, which they designated MAGE-Xp, they showed that exon 4, which is the last exon, contains the open reading frame and is present in a minimum of 5 copies in a 30-kb interval.
Lurquin et al. (1997) showed that the MAGEB1 promoter region is included within the coding exon of MAGEB4.
By hybridizing mouse genomic libraries with a MAGE1 probe, De Backer et al. (1995) identified 3 homologous genes: 2 of these mouse genes, Smage1 and Smage2, are more than 99% identical to each other and encode the same protein of 330 amino acids. The 5-prime noncoding region of Smage2 provides the potential for regulating the expression of the gene through several different promoters located in front of alternative first exons. The third gene, Smage3, has the structure of a processed transcript. It codes for a protein with only 11 amino acid substitutions with respect to the Smage1/2 product. Since the mouse Smage1 and Smage2 genes map to a region of the mouse X chromosome sharing homology of synteny with the human Xp22.1-p21.1 region, De Backer et al. (1995) concluded that these genes are homologous to the MAGE-Xp rather than to the MAGE-Xq genes. Smage1/2 transcripts were detected in several tumor and embryonal cell lines but not in normal mouse tissues with the exception of testis. Expression of Smage3 was found in embryos from day 11 to day 15.
Lurquin et al. (1997) showed that the predicted 347-amino acid MAGEB1 protein shares 49 to 68% sequence identity with MAGEB2, MAGEB3 (300152), and MAGEB4 (300153), the other 3 proteins encoded by the cluster of MAGE-related genes in chromosome Xp21.3. RT-PCR analysis of testis RNA revealed that MAGEB1 transcripts are alternatively spliced. Lurquin et al. (1997) demonstrated that the MAGEB1 gene has different transcription initiation sites under the control of promoters that are differentially regulated in testis and in tumors. The promoter directing transcription in tumor cells was induced by treatment with a demethylating agent, suggesting that activation of MAGEB1 in tumors results from a demethylating process.
Muscatelli et al. (1995) determined that the MAGEB1 gene, which they called MAGE-Xp, is located in the 160-kb critical interval defined for the locus involved in sex determination within Xp21 (DSS) and is 50 kb distal to the DAX1 gene (300473), which is the site of the mutation for X-linked congenital adrenal hypoplasia.
Using somatic cell hybrids and interspecific backcross analysis, De Backer et al. (1995) showed that the mouse Smage3 gene is autosomal and that Smage1 and Smage2 are located between the Dmd (300377) and the Ar (313700) loci on the mouse X chromosome, in a region syntenic to the human Xp22.1-p21.1 region.
Lurquin et al. (1997) reported that the MAGEB1 gene is located within a cluster of 4 MAGE-related genes that spans 42 kb in Xp21.3.
See 300016 for a discussion of the high frequency of genes on the X chromosome encoding proteins with the MAGE domain as well as other cancer-testis antigen genes (Ross et al., 2005).
Dabovic, B., Zanaria, E., Bardoni, B., Lisa, A., Bordignon, C., Russo, V., Matessi, C., Traversari, C., Camerino, G. A family of rapidly evolving genes from the sex reversal critical region in Xp21. Mammalian Genome 6: 571-580, 1995. [PubMed: 8535061] [Full Text: https://doi.org/10.1007/BF00352360]
De Backer, O., Verheyden, A.-M., Martin, B., Godelaine, D., De Plaen, E., Brasseur, R., Avner, P., Boon, T. Structure, chromosomal location, and expression pattern of three mouse genes homologous to the human MAGE genes. Genomics 28: 74-83, 1995. [PubMed: 7590750] [Full Text: https://doi.org/10.1006/geno.1995.1108]
Lurquin, C., De Smet, C., Brasseur, F., Muscatelli, F., Martelange, V., De Plaen, E., Brasseur, R., Monaco, A. P., Boon, T. Two members of the human MAGEB gene family located in Xp21.3 are expressed in tumors of various histological origins. Genomics 46: 397-408, 1997. [PubMed: 9441743] [Full Text: https://doi.org/10.1006/geno.1997.5052]
Muscatelli, F., Walker, A. P., De Plaen, E., Stafford, A. N., Monaco, A. P. Isolation and characterization of a MAGE gene family in the Xp21.3 region. Proc. Nat. Acad. Sci. 92: 4987-4991, 1995. [PubMed: 7761436] [Full Text: https://doi.org/10.1073/pnas.92.11.4987]
Ross, M. T., Grafham, D. V., Coffey, A. J., Scherer, S., McLay, K., Muzny, D., Platzer, M., Howell, G. R., Burrows, C., Bird, C. P., Frankish, A., Lovell, F. L., and 270 others. The DNA sequence of the human X chromosome. Nature 434: 325-337, 2005. [PubMed: 15772651] [Full Text: https://doi.org/10.1038/nature03440]