![model of spliceosome structure](https://www2.mrc-lmb.cam.ac.uk/wordpress/wp-content/uploads/spliceosome_structure_Slide1-14-150x150.jpg)
The spliceosome is a molecular machine, which together with RNA polymerases and ribosomes plays a critical role in basic gene expression. Due to its highly dynamic nature the structure of the spliceosome has remained elusive until now. Research by Kiyoshi Nagai’s group, in the LMB’s Structural Studies Division, has for the first time captured the spliceosome in a fully active, substrate-bound state, immediately after first catalytic reaction.