ONTOGENIC EXPRESSION PATTERNS OF TRANSCRIPTS ENCODING EGAM1 HOMEOPROTEINS DURING MURINE ORGANOGENESIS

Recently, we identified the structurally related homeoproteins EGAM1, EGAM1N, and EGAM1C both in preimplantation mouse embryos and mouse embryonic stem cells. When overexpressed in mouse embryonic stem cells, a series of EGAM1 homeoproteins are able to act as positive or negative regulators of differentiation and seem to also regulate the development of preimplantation embryos. Here, we investigated the ontogenic expression patterns of their transcripts during the generation of representative fetal organs. The expression levels of the Egam1 transcript were selectively higher in the adult eye among the organs examined, while Egam1n or Egam1c transcripts were expressed abundantly in the brain, eye, testis, and ovary during the fetal stages. These results, in combination with our previous observations, indicate that the respective transcripts encoding EGAM1 homeoproteins are expressed clearly not only in preimplantation mouse embryos, but also in specific embryonic organs, the extraembryonic placentae, and in adult organs, including the eye, in mice.