title: Interleukin 2 receptor signaling regulates the perforin gene through signal transducer and activator of transcription (Stat)5 activation of two enhancers.
abstract: Optimal T cell differentiation into effector cells with specialized functions requires the participation of cytokine receptor signals. In T helper cells, this process is controlled by chromatin changes and distal and proximal regulatory elements as well as specific transcription factors. Analogous events during cytotoxic T lymphocyte (CTL) differentiation remain to be identified. This process is known, however, to be crucially regulated by interleukin (IL)-2 receptor (R) signals. It is accompanied by the induction of perforin expression via a mechanism that does not entail proximal regulatory elements. In this report, transgenically expressed human perforin gene locus DNAs demonstrate that IL-2R signals target two IL-2-dependent enhancers approximately 15 and 1 kilobase upstream of the promoter. The most distal enhancer may also respond to TCR signals. In transient transfections, both enhancers required two identically spaced Stat-like elements for their activation, which was abolished by expression of a dominant negative signal transducer and activator of transcription (Stat)5 molecule, whereas a constitutively active Stat5 molecule bypassed the requirement for IL-2R signals. These results provide a molecular explanation for the activation of the perforin gene during CTL differentiation and complement the analysis of animals deficient in the activation of the IL-2R Stat signaling pathway by establishing perforin as a target gene.
authors.affiliation: Department of Microbiology, University of Miami School of Medicine, Miami, Florida 33136, USA.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: I
authors.initials: I
authors.lastname: Scordi
authors.forename: M J
authors.initials: MJ
authors.lastname: Smyth
authors.forename: M G
authors.initials: MG
authors.lastname: Lichtenheld
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D008894:Milk Proteins; D008969:Molecular Sequence Data; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid; D050799:STAT5 Transcription Factor; D015398:Signal Transduction / Q000235:genetics*; D013601:T-Lymphocytes / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D008894:Milk Proteins; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D054353:Perforin