Superinduction of human fibroblast interferon production: further evidence for increased stability of interferon mRNA.

摘要: Abstract Cytoplasmic polyadenylated interferon mRNA, synthesized in human diploid fibroblasts (FS-4 strain) largely within the first 3 hr of exposure to poly(I) poly(C), is approximately 850–900 nucleotides size (12 S) as determined by sedimentation dimethylsulfoxide denatured mRNA through a sucrose gradient and translation RNA each fraction microinjection into oocytes Xenopus laevis . Newly cytoplasmic has poly(A) length >100 step elution from poly(U)-Sepharose column with varying concentrations formamide subsequent eluted fraction. There pool translatable nuclear molecules which also sediment at 12 S. No poly(A)-lacking detectable. One hour after beginning poly(C) induction concentration higher than that pool. Interferon peaks 2 undetectable 4–5 while it between barely detectable 6 hr. The rate secretion culture FS-4 cells 2.5 3.5 shut off 6–8 cytoplasmic, phenol-extractable, declines half-life 0.5 1.0 during shutoff phase, does secretion. rapid production occurs 8 prevented when cultures are induced maintained 5,6-dichloro-1-β- d -ribofuranosylbenzimidazole (DRB, 40 μM), selective reversible inhibitor hnRNA synthesis. This leads an 10-fold increase cumulative yield 24 induction. In presence DRB, both decline virtually identical half-lives A theoretical analysis available data indicates increased functional stability major factor superinduction DRB. possibly results inhibition DRB synthesis rapidly turning over repressor involved inactivation or degradation mRNA. Since continues shorten unlikely result metabolism.