Functional dissection identifies a conserved noncoding sequence-1 core that mediates IL13 and IL4 transcriptional enhancement.
Conserved noncoding sequence (CNS)-1 has been shown to coordinately regulate the expression of the Th2 cytokine genes IL4, IL13, and IL5. We have used the interaction between CNS-1 and the human IL13 and IL4 promoters as a model to pursue the molecular mechanisms underlying CNS-1-dependent regulation of Th2 cytokine gene transcription. CNS-1 potently enhanced the activity of IL13 and IL4 promoter reporter vectors upon full T cell activation. Analysis of CNS-1 deletion mutants mapped enhancer activity to a short core (CNS-1-(270-337)) that contains three closely spaced cyclic AMP-responsive elements (CRE). CRE site 2 bound CRE-binding protein (CREB) and activating transcription factor (ATF)-2 in vitro and was essential for CNS-1-dependent up-regulation of IL13 transcription. Cotransfection of an IL13 reporter construct with expression vectors for wild type or mutant CREB and ATF-2 showed that CREB, but not ATF-2, regulates CNS-1 enhancer activity. Notably, chromatin immunoprecipitation analysis showed T cell activation recruits CREB and the coactivator CREB-binding protein (CBP)/p300 to the endogenous CNS-1. Moreover, CBP/p300 activity was essential for CNS-1-mediated enhancement of IL13 transcription. Collectively, these data define the region within CNS-1 responsible for enhancement of IL13 and IL4 transcription and suggest CREB/CBP-dependent mechanisms play an important role in facilitating Th2 cytokine gene expression in response to T cell receptor signaling.
Strempel
Jannine M
JM
Functional Genomics Laboratory, Arizona Respiratory Center, College of Medicine, University of Arizona, Tucson, Arizona 85724, USA.
Vercelli
Donata
D
D000818:Animals; D001483:Base Sequence; D050882:CREB-Binding Protein / Q000502:physiology; D017124:Conserved Sequence; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology; D004742:Enhancer Elements, Genetic; D006801:Humans; D018793:Interleukin-13 / Q000096:biosynthesis / Q000235:genetics*; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics*; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D018418:Th2 Cells / Q000378:metabolism; D014158:Transcription, Genetic
D017362:Cyclic AMP Response Element-Binding Protein; D018793:Interleukin-13; D015847:Interleukin-4; D050882:CREB-Binding Protein