2-Aminopurine selectively inhibits splicing of tumor necrosis factor alpha mRNA.
2-Aminopurine (2-AP) inhibits specific kinases that phosphorylate the alpha subunit of eukaryotic translation initiation factor 2. One of these, PKR, is also involved in signal transduction. We show here that 2-AP selectively inhibits expression of tumor necrosis factor alpha (TNF-alpha) mRNA in primary human lymphoid cells. 2-AP does not inhibit transcription of the human TNF-alpha gene, nor does it affect mRNA stability. Instead, the flow of short-lived precursor transcripts into mature TNF-alpha mRNA is blocked. When 2-AP is present during induction, unspliced TNF-alpha precursor transcripts accumulate at the expense of mRNA. Using RNase protection analysis with genomic probes for different exon-intron junctions, we show that 2-AP blocks splicing of TNF-alpha mRNA. Neither the TNF-beta nor the interleukin-1 beta gene shows such regulation. 2-AP also inhibits splicing of precursor RNA transcribed from an exogenous human TNF-alpha gene. Sequences within this gene thus confer sensitivity to 2-AP. Yet, control is not exerted at a specific splice site. Our results reveal the involvement of a 2-AP-sensitive component, expressed in functional form before induction, in the splicing of TNF-alpha mRNA.
Jarrous
N
N
Department of Molecular Virology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Osman
F
F
Kaempfer
R
R
D015075:2-Aminopurine / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003513:Cycloheximide / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D007375:Interleukin-1; D008070:Lipopolysaccharides; D012322:RNA Precursors; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D015075:2-Aminopurine; D003513:Cycloheximide; D013755:Tetradecanoylphorbol Acetate