On the relationship between human interferon alpha 1 and beta 1 genes

Area of Science:

• Molecular Biology
• Genetics
• Immunology

Background:

• Human interferon alpha 1 (IFN-alpha 1) and beta 1 (IFN-beta 1) genes share substantial nucleotide sequence identity (approx. 56%) in mature protein-coding regions.
• Interferons are crucial cytokines involved in the innate immune response against viral infections and cellular transformation.

Purpose of the Study:

• To investigate the genetic relationship and identify specific alleles between human IFN-alpha 1 and IFN-beta 1.
• To characterize a novel IFN-beta 1 allele resulting from a specific nucleotide substitution.

Main Methods:

• Construction of a complementary DNA (cDNA) library from human diploid fibroblasts (FS-4) induced with poly(I).poly(C).
• Hybridization screening using IFN-alpha 1 cDNA probes to isolate IFN-beta 1 cDNA clones.
• Restriction enzyme digestion (PstI, PvuII) and nucleotide sequencing to identify genetic variations.

Main Results:

• An IFN-alpha 1 cDNA probe successfully identified 15 IFN-beta 1 cDNA clones from a large library.
• A specific IFN-beta 1 cDNA clone exhibited altered restriction enzyme sites (loss of PstI and PvuII) due to a C-to-A substitution at nucleotide 277.
• This nucleotide change results in an amino acid substitution (Met-47 instead of Leu-47), defining the IFN-beta 1 Met-47 allele.

Conclusions:

• The high sequence similarity between IFN-alpha 1 and IFN-beta 1 facilitates cross-hybridization for gene isolation.
• A specific allele, IFN-beta 1 Met-47, has been identified, suggesting genetic diversity within the human IFN-beta 1 gene.
• Further investigation is warranted to determine the functional significance and prevalence of the IFN-beta 1 Met-47 allele in human genomic DNA.