Proteomic strategy for identifying Nullbasic-interacting proteins from HeLa-Nullbasic-mCherry cells. A. Overview of the proteomic approach for isolating Nullbasic (NB) binding proteins from cell nuclear extracts. B. Schematic diagrams of the VLP expression plasmids and an overview of the methods used to generate lentiviral VLPs. pCMV∆R8.91, pCMV-VSV-G and pLOX/CW-Nullbasic-FLAG-mCherry or pLOX/CW-FLAG-mCherry were co-transfected into HEK293T cells to produce VLPs containing either Nullbasic-FLAG-mCherry lentivector genome (VLP-NB-mCherry) or the control FLAG-mCherry genome (VLP-FLAG-mCherry). VLP-NB-mCherry and VLP-FLAG-mCherry were then transduced into HeLa cells in order to create cell lines stably expressing either the NB-mCherry proteins or FLAG-mCherry proteins. C. Nuclear protein lysates expressing NB-mCherry or FLAG-mCherry were separated by SDS-PAGE and protein bands were stained with Coomassie dye.