AIM: Studies of eukaryotes have yielded 2 translation initiation mechanisms: a classical cap-dependent mechanism and a cap-independent mechanism proceeding through the internal ribosomal entry site (IRES). We hypothesized that it might be possible to identify compounds that may distinguish between cap-dependent translation and cap-independent IRES-mediated translation. METHODS: To facilitate compound screening, we developed bicistronic reporter constructs containing a beta-galactosidase gene (beta-gal) and a secreted human placental alkaline phosphatase (SEAP) reporter gene. Following transcription, the beta-gal gene is translated by a cap-dependent mechanism, while SEAP expression is controlled by the IRES derived from either enterovirus 71 (EV-71) or encephalomyocarditis virus (EMCV). This assay could potentially identify compounds that inhibit SEAP expression (cap-independent) without affecting beta-gal activity (cap-dependent). RESULTS: Using a bicistronic plasmid-based transient transfection assay in the COS-1 cells, we identified amantadine, a compound that inhibited the IRES of EV71- and EMCV-mediated cap-independent translation but did not interfere with cap-dependent translation when the dose of amantadine was lower than 0.25 mg/mL. CONCLUSION: These results imply that amantadine may distinguish between cap-dependent translation and cap-independent IRES-mediated translation and can be used to regulate gene expression at a translational level.
AIM: Studies of eukaryotes have yielded 2 translation initiation mechanisms: a classical cap-dependent mechanism and a cap-independent mechanism proceeding through the internal ribosomal entry site (IRES). We hypothesized that it might be possible to identify compounds that may distinguish between cap-dependent translation and cap-independent IRES-mediated translation. METHODS: To facilitate compound screening, we developed bicistronic reporter constructs containing a beta-galactosidase gene (beta-gal) and a secreted human placental alkaline phosphatase (SEAP) reporter gene. Following transcription, the beta-gal gene is translated by a cap-dependent mechanism, while SEAP expression is controlled by the IRES derived from either enterovirus 71 (EV-71) or encephalomyocarditis virus (EMCV). This assay could potentially identify compounds that inhibit SEAP expression (cap-independent) without affecting beta-gal activity (cap-dependent). RESULTS: Using a bicistronic plasmid-based transient transfection assay in the COS-1 cells, we identified amantadine, a compound that inhibited the IRES of EV71- and EMCV-mediated cap-independent translation but did not interfere with cap-dependent translation when the dose of amantadine was lower than 0.25 mg/mL. CONCLUSION: These results imply that amantadine may distinguish between cap-dependent translation and cap-independent IRES-mediated translation and can be used to regulate gene expression at a translational level.
Authors: Guus Gijsbertus Hubert van den Akker; Federico Zacchini; Bas Adrianus Catharina Housmans; Laura van der Vloet; Marjolein Maria Johanna Caron; Lorenzo Montanaro; Tim Johannes Maria Welting Journal: Int J Mol Sci Date: 2021-05-14 Impact factor: 5.923
Authors: Mridul Kalita; Bing Tian; Boning Gao; Sanjeev Choudhary; Thomas G Wood; Joseph R Carmical; Istvan Boldogh; Sankar Mitra; John D Minna; Allan R Brasier Journal: Biomed Res Int Date: 2013-10-21 Impact factor: 3.411