A New Allele of Interferon-αl7 Gene Encoding IFN-α17b Is the Major Variant in Human Population

Abstract

Thirteen interferon (IFN)-α functional genes have been reported. Among these, a number of genes have allelic members (variants). In the case of IFN-αl7, five variants, IFN-αl7a, IFN-αl7b, IFN-αl7c, IFN-αl7d, and IFN-αT, are known. The variants differ from each other by base changes in the coding region, leading to differences in amino acid sequences. We have developed oligonucleotide primers for amplification of IFN-α17 gene(s) using polymerase chain reaction (PCR). Genomic DNA, obtained from over 28,000 normal healthy individuals and from four cell lines, were used as templates in PCR to amplify the IFN-αl7 gene sequences. The resulting PCR products were analyzed by restriction endonuclease digestion and DNA sequencing to identify the presence of variant sequences. The results show that a new variant of IFN-αl7 is abundantly present (∼70%) along with another variant, possibly IFN-αl7c (∼30%), in the genomic DNA of the population examined. This new variant, the protein product of which is identical to IFN-αl7b, differs from the gene for IFN-αl7b by a point mutation. We have named it IFN-αl7b', which is the only variant found in U-937, KG1, and EB-3 cell lines. Namalwa cells have IFN-αl7b' and, possibly, IFN-αl7c in equal proportions.