53] A procedure for isolation of alpha interferon genes with short oligonucleotide probes

Abstract

The chapter describes a procedure for the isolation of alpha interferon genes with short oligonucleotide probes. A method has been developed, which permitted the isolation of several human alpha interferon (IFN-α) genes from a human genomic library in Charon 4A bacteriophages with 17-base synthetic oligonucleotide probes. Previously, human IFN-α genes are isolated from complementary DNA (cDNA) libraries or genomic libraries with cDNA probes. The use of select, short, synthetic probes permits the isolation of the subsets of genes within a gene family represented in a genomic library. The screening procedure with 17-base probes described in the chapter is useful for the isolation of most genes from a human genomic library, although some conditions will vary according to the sequence of the probes. Procedure yielded three IFN-α genes, which had perfect homology with the two probes utilized. Even genes containing introns could be isolated from a genomic library with short and mixed probes provided the intron does not split the sequences of the probes to a size unable to maintain a stable hybrid. Changes at positions 42 and 133 result in the replacement of acidic residues with hydrophobic residues.