Two regions of the genome contain members of the MAGE gene family; Xqa
7-qter and Xp21.3. We isolated a transcript, MAGE Xp-2, by screening a
cDNA library from the human epithelial carcinoma cell line, HEp-2, us
ing autoantibodies from patients with systemic lupus erythematosus (SL
E), The open reading frame (ORF) of MAGE Xp-2 is entirely contained in
exon 4, a signature feature of the MAGE gene family. While MAGE Xp-2
shares genomic homology with MAGE Xp-1, the predicted proteins are qui
te divergent. Specific primers were designed to reliably distinguish b
etween MAGE Xp-1 and MAGE Xp-2 expression, MAGE Xp-2 is expressed in t
estis, but not in other normal tissues. It is also expressed strongly
in two of seven melanoma cell lines and one of four breast carcinomas.
MAGE gene expression may be important not only for tumor recognition
and cancer therapy, but, because it is the apparent target of autoanti
bodies in SLE sera, it may also play a role in autoimmune diseases. (C
) 1998 Academic Press.