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-alpha, IFN-beta, 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 blastocysts. Transcripts for IFN-alpha, but not for IFN-beta, 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-alpha transcripts present in (D-) P19 cells were cloned and the partial cDNA sequences determined. Mu IFN-alpha A and a new Mu IFN-alpha 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.

Characterization of the Murine Alpha Interferon Gene Family

“…Sequences diverging from previously sequenced alleles were deposited in GenBank ( Table 2). The sequence of IFN-␣12 had partially been published (35). Sequences of the pseudogenes, reconstructed from the fragments of C57BL/6 mice were deposited in the Third Party Annotation subset of the GenBank database (accession no.…”

“…COS-7 cells, seeded in 6-well plates at 150,000 cells per well, were transfected with the different IFN-␣-expressing constructs by using Fugene-6 reagent (Roche). At 24 h after transfection, cells were washed two times and incubated for 24 h in 1 ml of methionine-and cysteine-deficient Dulbecco's modified Eagle's medium (ICN) containing 1/10 of the normal methionine concentration (3 mg/liter) and 70 or 80 Ci of 35 S-labeled methioninecysteine mixture (Redivue Pro-mix; Amersham-Pharmacia Biotech) per ml. After 24 h of incubation at 37°C, supernatants were collected, centrifuged at 15,000 ϫ g to remove cell debris, and stored at Ϫ70°C.…”

“…35 S-labeled supernatants were treated with N-glycosidase F (Calbiochem) and, when necessary, with a cocktail of enzymes required for O-glycosylation removal (Calbiochem deglycosylation kit). Crude or treated supernatants were diluted in sample buffer (62.5 mM Tris [pH 6.8], 2% ␤-mercaptoethanol, 3% sodium dodecyl sulfate [SDS], 10% glycerol, 0,1% bromophenol blue) and run on TrisTricine, SDS-11% polyacrylamide gel electrophoresis (PAGE).…”

“…They are coded by an intronless multigene family clustered on murine chromosome 4 and in human chromosome 9. One IFN-␤ and multiple IFN-␣ genes were found in the mouse and human genomes (11,13,14,15,22,25,30,35,37,39,41,44,47,50). Other IFN-␣/␤ genes described include the murine limitin gene and the human IFN-gene, as well as the IFN-and IFN-ε/ genes that were found in both the human and murine genomes (Table 1) (2,9,24,32,46).…”

Role of IRF6 in epithelial cell-mediated host defence and inflammation

“…However, this family also functions in reproduction and development (Riego, Perez et al 1995, Bazer, Spencer et al 1997, Ozato, Tailor et al 2007), tumour suppression, apoptosis and embryonic development (Tanaka, Kawakami et al 1993, Kondo, Schutte et al 2002, Tsujimura, Nagamura-Inoue et al 2002. Specific IRF family members have well-established functions in development of immune cell lineages.…”