Insulin-activated Elk-1 recruits the TIP60/NuA4 complex to increase prolactin gene transcription
| Autor: | Muktar A. Mahajan, Frederick M. Stanley |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
endocrine system
Chromatin Immunoprecipitation Transcription Genetic animal diseases Mutant Biochemistry Chromatin remodeling Histones Endocrinology Transcription (biology) Two-Hybrid System Techniques Animals Humans Insulin p300-CBP Transcription Factors Luciferases Promoter Regions Genetic Molecular Biology Adaptor Proteins Signal Transducing ets-Domain Protein Elk-1 Messenger RNA biology Wild type Nuclear Proteins Acetylation Histone acetyltransferase Chromatin Assembly and Disassembly Molecular biology Prolactin Actins Chromatin Rats Histone Gene Expression Regulation biology.protein Trans-Activators Mutant Proteins hormones hormone substitutes and hormone antagonists Protein Binding |
| Zdroj: | Molecular and cellular endocrinology. 382(1) |
| ISSN: | 1872-8057 |
| Popis: | Insulin increases prolactin gene expression in GH4 cells through phosphorylation of Elk-1 (Jacob and Stanley, 2001). We preformed a reverse two-hybrid screen using Elk-1-B42 as bait to identify proteins from GH4 cells that might serve as co-activators or co-repressors for insulin-increased prolactin gene expression. A number of the components of the TIP60/NuA4 complex interacted with Elk-1 suggesting that Elk-1 might activate transcription by recruiting the TIP60 chromatin-remodeling complex to the prolactin promoter. Inhibition of insulin-increased prolactin-luciferase expression by wild type and mutant adenovirus E1A protein provided physiological context for these yeast studies. Inhibition of histone deacetylases dramatically increased both basal and insulin-increased prolactin gene transcription. Co-immune precipitation experiments demonstrated Elk-1 and TIP60 associate in vitro. Transient or stable expression of TIP60 activated insulin-increased prolactin gene expression while a mutated TIP60 blocked insulin-increased prolactin gene expression. Analysis of the prolactin mRNA by quantitative RT-PCR showed that insulin-increased prolactin mRNA accumulation and that this was inhibited in GH4 cells that stably expressed mutant TIP60. Finally, ChIP experiments demonstrate the insulin-dependent occupancy of the prolactin promoter by Elk-1 and TIP60. Our studies suggest that insulin activates prolactin gene transcription by activating Elk-1 that recruits the NuA4 complex to the promoter. |
| Databáze: | OpenAIRE |
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