ANALYSIS OF β-INTERFERON mRNA IN HUMAN CELLS

Abstract

This chapter presents an analysis of β-interferon messenger RNA (mRNA) in human cells. Inducibility of human interferon depends on the nature of the inducer and also the cell type. Thus, poly rI.rC induction of human fibroblast cells produces mainly or exclusively β type, while that produced by lymphoblastoid cells consists about 90% α and 10% β type. The chapter explains a study in which kinetics of induction of β-interferon mRNA in these two systems was determined by RNA hybridization with a cloned βcDNA and by translation in Xenopus oocytes. The time course of accumulation of β-interferon mRNA in poly rI. rC induced fibroblast cells and Sendai stimulated Namalva cells corresponded to the kinetics of β interferon synthesis in intact cells. In poly r1.rc-induced fibroblast cells, ßmRNA disappeared several hours after its appearance in cytoplasm reaching undetectable levels at 7 hours after induction. A decrease in the size of ßmRNA was observed whether the induction was done in the absence or presence of cycloheximide. ßmRNA detected in Namalva cells induced with Sendai virus has the same size as that detected in fibroblast cells; however, the kinetics of its synthesis and degradation does not show the transiency found in poly rI.rC induced fibroblasts. The accumulation of β interferon mRNA in Sendai induced Namalva cells is maximal at 6 hours after induction and reaches an undetectable level by 24–48 hours after induction. This suggested that the mechanism of regulation of β interferon gene expression in poly rI.rC induced fibroblast cells and sendai-induced Namalva cells is different.