Jyotishman Veepaschit, Aravindan Viswanathan, Rémy Bordonné, Clemens Grimm, and Utz Fischer
Nucleic Acids Research, gkab158, https://doi.org/10.1093/nar/gkab158
Formation of RNA-protein complexes often requires assisting factors in vivo. An example are UsnRNPs, the major building blocks of spliceosomes, whose formation depends on the Survival Motor Neuron (SMN) complex. In this study, an integrative structural biology approach was used to establish a comprehensive model of the SMN complex. Its core is formed by several copies of SMN arranged with alternating polarity. This creates a central platform onto which the Gemin6/7/8 module is recruited. SMN’s N-terminal parts extrude via flexible linkers from the core and enable binding of Gemin2 and UsnRNP proteins. Our data identify the SMN complex as a multivalent hub collecting UsnRNP proteins in its periphery to allow their joining with UsnRNA.