Mechanism of action of a distal NF-kappaB-dependent enhancer.
The monocyte chemoattractant protein 1 gene (MCP-1) is regulated by TNF through an NF-kappaB-dependent distal enhancer and an Sp1-dependent promoter-proximal regulatory region. In the silent state, only the distal regulatory region is accessible to transcription factors. Upon activation by tumor necrosis factor, NF-kappaB binds to the distal regulatory region and recruits CBP and p300. CBP and p300 recruitment led to specific histone modifications that ultimately enabled the binding of Sp1 to the proximal regulatory region. During this process, a direct interaction between the distal and proximal regulatory regions occurred. Sp1, NF-kappaB, CBP, and p300 were required for this interaction. CBP/p300-mediated histone modifications enhanced the binding of the coactivator CARM1 to the distal regulatory region. CARM1, which is necessary for MCP-1 expression, was not required for distal-proximal region interactions, suggesting that it plays a later downstream activation event. The results describe a model in which the separation of the distal enhancer from the promoter-proximal region allows for two independent chromatin states to exist, preventing inappropriate gene activation at the promoter while at the same time allowing rapid induction through the distal regulatory region.
Teferedegne
Belete
B
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA.
Green
Myesha R
MR
Guo
Zhu
Z
Boss
Jeremy M
JM
D000818:Animals; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D051379:Mice; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism; D041681:NIH 3T3 Cells; D017434:Protein Structure, Tertiary; D011484:Protein-Arginine N-Methyltransferases / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism
D018932:Chemokine CCL2; D002843:Chromatin; D016328:NF-kappa B; D034741:RNA, Small Interfering; D016329:Sp1 Transcription Factor; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D011484:Protein-Arginine N-Methyltransferases; C119966:coactivator-associated arginine methyltransferase 1; D050880:p300-CBP Transcription Factors