Northern Blot Analysis

In the analysis of gene expression, the steady-state level of RNA transcripts is one of the most convenient parameters used to monitor the gene activity in cell lines and tissues. A variety of methods, such as S1 hybridization, RNase protection, and Northern blotting, can be used to measure RNA levels, and the choice of the best assay system depends largely on the type of information required, levels of sensitivity, and limitations of the particular in vivo system being examined. This chapter details the method for analyzing RNA by Northern blotting, which basically involves the isolation of RNA, its size fractionation by electrophoresis, transfer to membrane, and detection by nucleic acid hybridization and autoradiography.