![](https://parts.igem.org/images/partbypart/icon_rbs.png)
Part:BBa_K1442024
NKRF IRES
This is an Internal Ribosome Entry Site (IRES) acting in mammalian cells. It allows translation initiation in the middle of an RNA strand which is required for the fuctioning of our replicon as there are multiple protein coding regions separated by structural nucleotide sequences interspersed throuhgout the RNA strand. We chose to investigate two IRES sequences to compare the relative efficiency and determine which was better for incorporation into our system. These were the Encephalomyocarditis virus (EMCV) and the IRES derived from the NF-kappaB repressor factor (NKRF) untranslated region.
<NKRF is a transcriptional repressor protein that is essential in the immune response and acts to mediate the translational efficiency of other cellular proteins. The IRES used in this experiment is dervied from the 3' untranslated region of the protein mRNA.
Oumard and Hennecke 2000 indicates that this IRES has a 30 times higher translational efficiency than EMCV IRES and significantly higher than the poliovirus also, in HeLa cells. As our experiment is in Huh 7.5 cells we decided to test both the EMCV (already previously confirmed to work in Huh7.5) and NKRF which may or may not give us significantly better translational efficiency. </p>![](https://static.igem.org/mediawiki/parts/f/fa/NKRF_efficiency.jpg)
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000INCOMPATIBLE WITH RFC[1000]Illegal BsaI.rc site found at 340
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