Novel role of hnRNP-A2/B1 in modulating aryl hydrocarbon receptor ligand sensitivity
| Autor: | Yoshiaki Miura, Ken-ichi T. Suzuki, Eun-Young Kim, See-Wun Cho, Hisato Iwata, Tatsuhiko Miyazaki, Masato Nose |
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| Rok vydání: | 2014 |
| Předmět: |
Mice
Inbred MRL lpr Polychlorinated Dibenzodioxins Genotype Immunoprecipitation Health Toxicology and Mutagenesis Carbazoles Ligands Response Elements Transfection urologic and male genital diseases Toxicology Mice Transactivation immune system diseases Chlorocebus aethiops Heterogeneous-Nuclear Ribonucleoprotein Group A-B Animals skin and connective tissue diseases EC50 Mice Inbred C3H Reporter gene biology Chemistry General Medicine respiratory system Ligand (biochemistry) Aryl hydrocarbon receptor Molecular biology respiratory tract diseases Receptors Aryl Hydrocarbon COS Cells Immunology RNA splicing biology.protein |
| Zdroj: | Archives of Toxicology. 89:2027-2038 |
| ISSN: | 1432-0738 0340-5761 |
| Popis: | The aryl hydrocarbon receptor (AHR) is responsible for susceptibility to its ligand-dependent responses. However, the effect of non-AHR factors is less clear. To explore the non-AHR factors, we used two mouse strains with different AHR genetic variants, namely C3H/lpr and MRL/lpr strains with Ala and Val as the 375th amino acid residue, respectively. To assess the contribution of AHR alone, COS-7 cells transiently expressing AHR from each strain were treated with 6-formylindolo[3,2-b]carbazole (FICZ) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and xenobiotic-responsive element (XRE)-driven reporter gene activities were measured. FICZ-EC50 values for the C3H/lpr and MRL/lpr AHR-mediated transactivation were 0.023 and 0.046 nM, respectively, indicating a similar susceptibility in both AHR genotypes. In contrast, C3H/lpr AHR was fourfold more sensitive to TCDD than MRL/lpr AHR. By a pull-down assay using a XRE-containing PCR product as bait and the hepatic nuclear extracts of both FICZ-treated mouse strains, we identified two interacting proteins as heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP-A2) and its splicing variant (hnRNP-A2b). Immunoprecipitation assays demonstrated the AHR interaction with hnRNP-A2/B1. When hnRNP-A2 was co-expressed with the MRL/lpr or C3H/lpr AHR in COS-7, FICZ treatment decreased EC50 to about threefold in both AHR genotypes, compared with EC50 in AHR alone. Similarly, hnRNP-A2b co-expression also lowered the FICZ-EC50 values. In TCDD-treated COS-7, responses depended on the AHR genotype; while no change in TCDD-EC50 was observed for C3H/lpr AHR when hnRNP-A2 was co-expressed, the value was reduced to nearly tenfold for MRL/lpr AHR. Co-transfection with hnRNP-A2b attenuated the AHR sensitivity to TCDD. In conclusion, the hnRNP-A2/B1 interacting with AHR may be a modulator of the AHR ligand sensitivity. |
| Databáze: | OpenAIRE |
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