Difference between revisions of "Part:BBa K4469009"
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During the translation of mRNA in eukaryotic organisms, the 5’ cap,7-methyl guanosine residue, of mRNA is required for initation of translation by binding to the translation initiation factors(eIFS) and thus recruiting ribosomes (Richter & Sonenberg, 2005). | During the translation of mRNA in eukaryotic organisms, the 5’ cap,7-methyl guanosine residue, of mRNA is required for initation of translation by binding to the translation initiation factors(eIFS) and thus recruiting ribosomes (Richter & Sonenberg, 2005). | ||
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However, it is discovered that many viruses and cells include the internal ribosomal entry site (IRES) element to replace the function of cap and some or all initiation factors required for translation(Martinez-Salas et al., 2017). Therefore, in order to have co-expression of two genes in a single vector, the IRES could be used for second gene expression under the same promoter in a cap-independent manner(ibid). It is proposed that by putting the IRES element upstream of the second open reading frame to form a complex secondary and tertiary structure such as a stem-loop structure, it would be able to recruit the 40S ribosomal subunit by using other eukaryotic eIFs and cellular RNA-binding proteins(RBPs)(ibid). For the reseach uses and plasmid design, the encephalomyocarditis virus (EMCV) IRES is most widely used due to its proved functionality in a wide variety of cell types(ibid). In specific, EMCV IRES element is classified as types II IRES that requires the C-terminal region of eIF4G, eIF4A, eIF2, and eIF3 to assemble 48S initiation complexes in vitro, but are independent of eIF4E(de Breyne, 2009). | However, it is discovered that many viruses and cells include the internal ribosomal entry site (IRES) element to replace the function of cap and some or all initiation factors required for translation(Martinez-Salas et al., 2017). Therefore, in order to have co-expression of two genes in a single vector, the IRES could be used for second gene expression under the same promoter in a cap-independent manner(ibid). It is proposed that by putting the IRES element upstream of the second open reading frame to form a complex secondary and tertiary structure such as a stem-loop structure, it would be able to recruit the 40S ribosomal subunit by using other eukaryotic eIFs and cellular RNA-binding proteins(RBPs)(ibid). For the reseach uses and plasmid design, the encephalomyocarditis virus (EMCV) IRES is most widely used due to its proved functionality in a wide variety of cell types(ibid). In specific, EMCV IRES element is classified as types II IRES that requires the C-terminal region of eIF4G, eIF4A, eIF2, and eIF3 to assemble 48S initiation complexes in vitro, but are independent of eIF4E(de Breyne, 2009). | ||
Latest revision as of 18:15, 29 September 2022
Internal ribosome entry site (IRES)
During the translation of mRNA in eukaryotic organisms, the 5’ cap,7-methyl guanosine residue, of mRNA is required for initation of translation by binding to the translation initiation factors(eIFS) and thus recruiting ribosomes (Richter & Sonenberg, 2005).
However, it is discovered that many viruses and cells include the internal ribosomal entry site (IRES) element to replace the function of cap and some or all initiation factors required for translation(Martinez-Salas et al., 2017). Therefore, in order to have co-expression of two genes in a single vector, the IRES could be used for second gene expression under the same promoter in a cap-independent manner(ibid). It is proposed that by putting the IRES element upstream of the second open reading frame to form a complex secondary and tertiary structure such as a stem-loop structure, it would be able to recruit the 40S ribosomal subunit by using other eukaryotic eIFs and cellular RNA-binding proteins(RBPs)(ibid). For the reseach uses and plasmid design, the encephalomyocarditis virus (EMCV) IRES is most widely used due to its proved functionality in a wide variety of cell types(ibid). In specific, EMCV IRES element is classified as types II IRES that requires the C-terminal region of eIF4G, eIF4A, eIF2, and eIF3 to assemble 48S initiation complexes in vitro, but are independent of eIF4E(de Breyne, 2009).
References
Richter, & Sonenberg, N. (2005). Regulation of cap-dependent translation by eIF4E inhibitory proteins. Nature, 433(7025), 477–480. https://doi.org/10.1038/nature03205
Martinez-Salas, Francisco-Velilla, R., Fernandez-Chamorro, J., & Embarek, A. M. (2017). Insights into Structural and Mechanistic Features of Viral IRES Elements. Frontiers in Microbiology, 8, 2629–2629. https://doi.org/10.3389/fmicb.2017.02629
de Breyne, Yu, Y., Unbehaun, A., Pestova, T. V., & Hellen, C. U. . (2009). Direct functional interaction of initiation factor eIF4G with type 1 internal ribosomal entry sites. Proceedings of the National Academy of Sciences - PNAS, 106(23), 9197–9202. https://doi.org/10.1073/pnas.0900153106