No abstract

The human prototypical SR protein SRSF1 is an oncoprotein that contains two RRMs and plays a pivotal role in RNA metabolism. We determined the structure of the RRM1 bound to RNA and found that the domain binds preferentially to a CN motif (N is for any nucleotide). Based on this solution structure, we engineered a protein containing a single glutamate to asparagine mutation (E87N), which gains the ability to bind to uridines and thereby activates SMN exon7 inclusion, a strategy that is used to cure spinal muscular atrophy. Finally, we revealed that the flexible inter-RRM linker of SRSF1 allows RRM1 to bind RNA on both sides of RRM2 binding site. Besides revealing an unexpected bimodal mode of interaction of SRSF1 with RNA, which will be of interest to design new therapeutic strategies, this study brings a new perspective on the mode of action of SRSF1 in cells.

Protein–RNA complex formation is at the center of RNA metabolism and leads to the modulation of protein and RNA functions. We propose here a step-by-step guide to investigate these interactions including the identification of the protein and RNA parts involved in complex formation, the determination of the affinity of the complex and the characterization of the protein–RNA interface at amino acid and nucleotide level. Moreover, we briefly review the methods that are the most often used to obtain this information using primarily examples from our lab and finally mention what we perceive as the next challenges in the field.