Expression of cancer-testis antigens of the Mage family in mouse oocytes and early embryos

Abstract

Cancer-testis antigens of the Mage family (Melanoma antigens) are expressed predominantly in the spermatogenic and cancer cells, but some genes of this family are expressed ubiquitously. Expression patterns and functional role of Mage family antigens in the regulation of cellular processes in normal embryonic and definitive cells are virtually unknown. Comparative immunofluorescent analysis of Mage expression in mouse oocytes and early embryos identified the expression of Mage antigens at all stages studied. The greatest intensity of the fluorescent staining was detected in the epiblasts and the extraembryonic structures of the egg cylinder at E6.5 stage. At all studied developmental stages of the mouse oocyte and the early embryo, the localization of Mage antigens was found predominantly in the cytoplasm. Quantitative real-time PCR showed that expression levels of most Mage genes in cells of the epiblast and ectoplacental cone were similar, while the gene expression levels of Mage-a10, Mage-b16, and Mage-b18 were higher in cells of the ectoplacental cone than in epiblast cells. Thus, for the first time, our analysis has shown that the Mage family antigens are expressed at the early stages of mouse development and may be involved in the regulation of earliest events of embryogenesis.