Mojdeh Mahdiannasser - Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
Ali NAJAFI - Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
POUYA Salehipour - Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
Mohammad Hossein Modarressi - Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran

The 5′ untranslated region includes exons located upstream of the coding sequence. They are transcribed into mRNA, but not translated into protein. Genes encoding transcription factors, proto-oncogenes, tumor suppressors, growth factors and their receptors tend to produce transcripts with a longer and more complicated 5′UTR region, containing various elements such as the upstream open reading frame (uORF) and the internal ribosome entry site (IRES). Such genes are highly regulated at the translational level.Aim Regarding the significance of the 5′UTR region in the regulation of gene expression, we report a method to identify different regulatory elements in the 5′UTR region.Method and Result In order to locate the regulatory elements including uORF and IRES in the 5′UTR region, the sequence of the mRNA is screened using UTRdb, UTRscan, and RegRNA. Additionally, the sequences of the 5′UTR in different species are obtained from NCBI and aligned using the MAFFT multiple sequence alignment program to identify conserved regulatory elements. Finally, the RNAfold web server from the Vienna RNA and MFOLD program are used to determine secondary structures as well as the corresponding free energy changes (ΔG) related to the folding of the 5′UTR.Conclusion There is massive evidence that the deregulation of gene-specific translation plays a critical role in oncogenic transformation and tumor progression. Further studies are necessary to ascertain the function and the specific roles of uORF and IRES in translational regulation, considering various environmental conditions, such as hypoxia.

5′ untranslated regions, IRES, uORF, Translational regulation