Purified recombinant D. melanogaster proteins Gem2, Smn and icln were mixed with human SmD1, SmD2, SmE, SmF and SmG to reconstitute the 8S spliceosome assembly intermediate.

Electron microscopy 3D reconstruction was used to position those elements of the 8S complex that could not be traced in the crystallographic electron density.

Interaction in vitro; proteins produced as a recombinant fusion proteins in bacterial system.