Fibroblast interferon from a human amniotic cell line: a strategy for rapid molecular cloning

A strategy for rapid cloning and identification of cDNA clones was employed to obtain fragments of the gene for human fibroblast (beta) interferon. A human amniotic cell line (UAC), widely used for interferon assay, yielded high titers of beta-interferon and was used as a source for cDNA synthesis. Recombinant clones were screened by a combination of hybridization conditions: (a) comparing clones that hybridized with radioactive cDNA from induced UAC cells vs cDNA from cells not induced for beta-IFN; (b) using a synthetic oligonucleotide proble complementary to a region of the beta-IFN gene. Among clones selected on the basis of their positive response to both screening procedure, one (4F7) was sequenced and shown to be highly homologous to the beta-IFN gene. This clone was used as a probe to screen a human chromosomal DNA library, yielding the entire chromosomal beta-IFN gene. A "Northern" hybridization analysis of UAC mRNA from uninduced and induced cells revealed the existence of a single molecular species of mRNA for beta-IFN with the expected molecular weight.