RELATIVE TRANSCRIPTIONAL INDUCIBILITY OF THE HUMAN INTERFERON-ALPHA SUBTYPES CONFERRED BY THE VIRUS-RESPONSIVE ENHANCER SEQUENCE

This paper addresses the role of transcriptional regulation in the det ermination of the levels of expression of different interferon-alpha s ubtypes secreted from Namalwa cells following infection with Sendai vi rus, Using RT-PCR to determine the relative abundance of mRNA species coding for the various subtypes, we found a general correlation with c orresponding protein levels, indicative of a role for transcriptional control in the determination of levels of individual subtypes. We have used reporter gene constructs to compare the inducibility of the viru s-response elements from the IFNA1, A2, A4, and A14 subtype genes clon ed upstream of a secreted alkaline phosphatase gene, The inducibility of these reporter gene constructs broadly correlated with the relative mRNA abundances in both transiently and stably transfected Namalwa ce lls, During work with stable cell lines, we found that G418, the drug used for the selection of transfected cells, inhibited the induction o f interferon by both Sendai virus and double-stranded RNA. This inhibi tion was reversible when G418 was removed from the medium 24 h before the addition of virus.