Messenger RNA Fractionation on Neutral Sucrose Gradients
The separation of RNA on the basis of size by sucrose gradient fractionation is
The separation of RNA on the basis of size by sucrose gradient fractionation is a technique frequently employed in a cloning strategy (1 –3 ). After production of poly(A)+ mRNA by affinity chromatography (see Chapter 16 ) the RNA can be fractionated once or twice on sucrose gradients to produce a subpopulation of mRNA enriched for a particular species. The RNA fractions from the gradient can be assayed by in vitro translation and subsequent immunoprecipitation or bioassay of the products (see Chapters 19 –Chapters 22 ).