Expression of a synthetic human interferon-α 1 gene with modified nucleotide sequence in mammalian cells

Abstract

We have constructed a recombinant interferon (IFN) gene whose coding region is a chemically synthesized human (Hu)IFN-α 1 gene [Edge et al., Nature 292 (1981) 756–762] encoding the same protein as its natural counterpart while possessing important modifications. These modifications were introduced in order to: (1) change codon usage, (2) destroy integrity of repeated and complementary oligodeoxynucleotides in the coding region, (3) introduce an intron, (4) substitute other sequences for the IFN specific 3'- and 5'-flanking sequences and (5) remove the leader sequence (which encodes for the signal peptide). We report here on the transfection and isolation of murine cells which contain low-copy-number insertions of our recombinant gene. These lines maintain a high steady-state level of biologically active HuIFN-α in the cytoplasm, produced from mRNAs of M r expected for correctly processed transcripts. These results show directly that the leader sequence is essential for secretion of IFN proteins. They also argue against a crucial role of the particular features of the transcribed sequence of the natural HuIFN-α 1 gene in regulating its expression.