Further heterogeneity of human alpha interferon mRNA species.

Translationally active (in Xenopus oocytes) human alpha interferon (IFN) messenger RNA's (mRNA's) derived from Sendai virus--induced leukocyte cultures display a bimodal distribution of RNA lengths on electrophoresis through agarose-CH3HgOH gels. The major population (alpha s) consists of mRNA of length 0.7 to 1.4 kilobases, while the minor population (alpha L) consists of RNA of length 1.6 to 3.5 kilobases. Induction of human leukocytes in the presence of 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB; 100 micromolar) appears to inhibit the accumulation of IFN-alpha s and to enhance that of IFN-alpha L mRNA's (average length about 1.8 kilobases in preparations from DRB-treated cells). Interferons derived from the alpha s mRNA's represent the group of previously recognized alpha interferons while the alpha L interferons are distinguishable from this group by their lower heterospecific activity on bovine cells compared to human cells, their apparent slower mobility in sodium dodecyl sulfate--polyacrylamide gels, and their apparent heteroclitic response toward an antiserum to IFN-alpha.