DIFFERENTIAL CONSTITUTIVE EXPRESSION OF INTERFERON GENES IN EARLY MOUSE EMBRYOS

Recent evidence suggests that several processes during mammalian embry ogenesis may be regulated by IFNs or IFN-like molecules. With the use of MAPPing, the simultaneous presence of transcripts homologous to IFN -alpha, IFN-beta, IRF-1, and IRF-2 was examined in mouse embryos and i n embryonal carcinoma (EC) P19 cells, which are equivalent to epiblast cells of the early postimplantation blastocyst. Transcripts for IFN-a lpha, but not for IFN-beta, were detected as maternal transcripts in t he ovulated oocyte and persisted over early embryogenesis. IRF-1 trans cripts appeared only after the first cell cleavage in the two-cell sta ge embryo. IRF-2 transcripts were analyzed only in EC P19 cells and we re found in both undifferentiated (D-) and differentiated (D+) cells. The IFN-alpha transcripts present in (D-) P19 cells were cloned and th e partial cDNA sequences determined. Mu IFN-alpha A and a new Mu IFN-a lpha species (Mu IFN-alpha 12) were isolated from (D-) P19 cells. The presence of constitutive IFN-alpha transcripts in early mouse embryos suggests a role for these molecules during embryogenesis. (C) 1995 Wil ey-Liss, Inc.