AbstractsEngineering

The aim of this thesis is to understand RNA-RNA interactions steering cellular functions, as in the case of this thesis the structure of mRNA(Sirt1) in complex with microRNA-34a (miR-34a). MiR-34a regulates the cancer protein p53 via Sirt1 modulation. This work will be the basis for future drug design and the understanding of misguided regulation in cancer. The miR-34a binds to the mRNA(Sirt1) 3’ untranslated region (3’-UTR) and will either inhibit the translation of the protein Sirtuin 1 by capturing its mRNA or by degrading it. p53, a key activator of miR-34a, prevents cancer development by inducing programmed cell death (apoptosis) on cells with DNA damage. In contrast, the protein Sirtuin 1 (Sirt1) has been shown to help cells with DNA damage to survive by down regulating the activity of protein p53 and will therefore increase the risk of cancer development. Studying the interaction between the mRNA(Sirt1) and miR-34a can present valuable information on the structure of the complex as well as the mode miR-34a uses to inhibit translation of mRNA(Sirt1) leading to down regulation of protein Sirtuin 1 and therefore prevent cancer development. For the elucidation of this question different biochemical and biophysical methods were applied, such as in vitro transcription, gel electrophoresis, RNA purification with gel, crush & soak and Cicular Dichroism (CD) melting studies. For this thesis work, the target sequence in mRNA(Sirt1) was optimized and purified so melting studies could be carried out. For future structural characterization using Nuclear Magnetic Resonance (NMR) studies with the miR-34a also produced in the lab. The mRNA(Sirt1) target sequence was produced and purified with the final yield of 0.02%. The results show that the sequence is highly ATP dependent and suggest the ratio between the nucleotides ATP/CTP to be 1:2. Low yield of purified mRNA(Sirt1) was received and still contained some impurities, which imply that another method than crush & soak should be used when purifying. The results, indicate that High-Preformance Liquid Chromatography (HPLC) might be a better solution for the pufication process. The melting profiles done on mRNA(Sirt1) show that the secondary structures decrease with an increase in temperature. Accroding to the results, the mRNA(Sirt1) sequence is folded in room temperature, though not very stable. The wavelength which provided the best resolution was at 268 nm and the melting point of mRNA(Sirt1) was determined to 44 °C. This thesis also contains an educational part, where an educational material was provided and testing was conducted for the subject Chemistry 2 for students age 18 and the material was evaluated with qualitative methods together with pedagogical methods. The study showed that the student can develope the different abilities stated in the curriculum with the material created. The results also showed that the students preferably choose cultural arguments when dicussing socio scientific question, rather than economical,…