Prediction and in vitro mapping of rG4s in transcripts has suggested presence of rG4s in 5’UTRs and 3’UTRs of several cancer related transcripts. This important disease relationship needs to be further explored and rG4 dependent mechanisms regulating gene expression should be identified. In the field, only few reports of rG4s affecting translation, stability or transport of mRNAs are available and most work on translation are based on in vitro results. Only few rG4 interacting proteins have been identified and hardly anything is known about the consequences of these interactions on the mRNA life cycle. Hence, unbiased, genome wide approaches are needed to develop a deeper understanding of rG4 function. Exploring some of these avenues was the main goal of this project. Here I have shown, in a unbiased manner, that a single rG4 in the 5’UTR hampers translation of mRNAs while single rG4s in other positions in mRNAs did not have this effect. Next, in a collaborative effect I started to catalogue the protein interaction partners of the NRAS rG4. This lead to the identification of multiple interactors and further study of one of these novel rG4 interactors revealed a strong disease relationship with a possible mechanistic link to disease development. This work can be considered as strong basis for future projects that will result in more detailed description of rG4 function. Lastly, development of a reporter system that is able to identify new upstream regulators of rG4 function has great potential to determine whole pathways regulating rG4 dependent mRNA fate. This reporter system can also easily be used to screen for small molecules that can specifically target rG4 dependent gene expression.
Overall my work has opened up new perspectives on rG4 mediated function and highlighted new disease relationships.
