Differential constitutive expression of interferon genes in early mouse embryos

Abstract
Recent evidence suggests that several processes during mammalian embryogenesis may be regulated by IFNs or IFN-like molecules. With the use of MAPPing, the simultaneous presence of transcripts homologous to IFN-α, IFN-β, IRF-1, and IRF-2 was examined in mouse embryos and in embryonal carcinoma (EC) P19 cells, which are equivalent to epiblast cells of the early postimplantation blastocyst. Transcripts for IFN-α, but not for IFN-β, were detected as maternal transcripts in the ovulated oocyte and persisted over early embryogenesis. IRF-1 transcripts appeared only after the first cell cleavage in the two-cell stage embryo. IRF-2 transcripts were analyzed only in EC P19 cells and were found in both undifferentiated (D) and differentiated (D+) cells. The IFN-α transcripts present in (D) P19 cells were cloned and the partial cDNA sequences determined. Mu IFN-αA and a new Mu IFN-α species (Mu IFN-α12) were isolated from (D) P19 cells. The presence of constitutive IFN-α transcripts in early mouse embryos suggests a role for these molecules during embryogenesis.