Zinc Finger Protein 808 (ZNF808)

IRES activity of the test sequence was indicated by the ratio between firefly luciferase and Renilla luciferase activities.. Among all tested 5'UTR isoforms, most constructs showed a very low firefly/Renilla luciferase ratio that was not above the empty vector (pRF-Luc2) control.

Only the Alu exon inclusion 5'UTR construct of ZNF808 showed a significant firefly/Renilla ratio comparable to the Encephalomyocarditis virus (EMCV)-IRES-1 positive control and much higher (approximately fourfold) than its Alu exon skipping counterpart. This result is consistent with the observation that the Alu exon inclusion 5'UTR of ZNF808 showed a significant increase in translational efficiency, suggesting a potential IRES created by Alu exon inclusion.