Analysis of RNA by Northern Blotting

Northern hybridization is used to measure the amount and size of RNAs transcribed from eukaryotic genes and to estimate their abundance. No other method is capable of obtaining these pieces of information simultaneously from a large number of RNA preparations; northern analysis is therefore fundamental to studies of gene expression in eukaryotic cells. To prepare a northern blot for hybridization, RNA must be separated according to size through a denaturing agarose or polyacrylamide gel and transferred to a solid support in a way that preserves its topological distribution within the gel. These important steps in northern analysis are discussed here.