Isolation and expression of rat interferon beta gene and growth-inhibitory effect of its expression on rat glioma cells

Rat interferon beta (IFN beta) was cloned from a part of rat genomic DNA by the polymerase chain reaction (PCR) with reference to the nucleotide sequence data of a mouse IFN beta. The sequence result showed that the clone had 555 bp of open reading frame (ORF) which encoded a 184-amino acid polypeptide. Comparison of our data with those of mouse and human IFN beta revealed 86.7 and 67.6% homology at the nucleotide level, and 76.2 and 48.9% homology at the amino acid level, respectively. This ORF was inserted into an expression vector, pCAGGS, and COS-1 cells were then transfected with the plasmid encapsulated in cationic multilamellar liposomes. From the results of reverse transcription-PCR and cytopathic activity assay, this ORF expressed IFN beta in COS-l cells. When the cultured cells of rat glioma cell line T9 were transfected with the plasmid, their growth was markedly suppressed due to the expression of rat IFN beta. (C) 1997 Academic Press.