Abstract
More than one 80 S monosome can translate an mRNA molecule at a time producing polysomes. The most widely used method to separate 40 S and 60 S ribosomal subunits from 80 S monosomes and polysomes is a high-velocity centrifugation of whole cell extracts in linear sucrose gradients.
This polysome profile analysis technique has been routinely used to monitor translational fitness of cells under a variety of physiological conditions, to investigate functions of initiation factors involved in translation, to reveal defects in ribosome biogenesis, to determine roles of 5' UTR structures on mRNA translatability, and more recently for examination of miRNA-mediated translational repression (see an application of this protocol on Polysome analysis for determining mRNA and ribosome association in Saccharomyces cerevisiae).