Characterization of a mouse interferon gene locus II. Differential expression of α-interferon genes

A cluster of four MuIFN-α genes was recently isolated and characterized (1); one of the genes in this cluster had, in the coding region, an internal deletion of 5 amino acids. Bacterial expression plasmids were constructed to examine the effect of this deletion on the antiviral activity of the MuIFN-α₄ peptide and it was found that α₄ interferon peptide had a 100-fold lower antiviral activity than full length α-interferon proteins when expressed in E.coli.Three of the four MuIFN-α genes identified were expressed coordinately in L-cells infected with NDV. The relative levels of α₄ mRNA were substantially higher than the levels of the other α mRNAs. Comparison of the 5′ end flanking sequences of these four a interferon genes revealed that the promoter sequences of α₁, α₅ and α₆ are more homologous to each other than to the α₄ promoter which also contains a G rich cluster not seen in the other three promoters.