Figure 1:

Cell extract versus purified RNP preparations for single molecule characterization. Prior to single molecule microscopy imaging, cell extract is prepared by culturing a cell line of choice to a high density and subsequently subjecting the cells to multiple rounds of centrifugation. (1) The isolated soluble fraction makes up crude cell extract. (2) In order to follow RNP interactions with other biomolecules, crude extracts can be supplemented with purified biomolecules thereby creating partially reconstituted cell extracts. (3) If desired and/or possible, crude extract can be further purified using traditional biomolecule purification strategies (e.g. affinity tags, ion exchange, gel filtration, etc.) to fully isolate and image the RNP of choice in the absence of complex cellular extract components.