ABSTRACT
Molecular biology studies usually involve the analysis of gene expression and structural characterization of DNA and RNA molecules. These procedures rely heavily on nucleic acid hybridization, such as Southern blots, northern blots, dot blots, microarrays, in situ hybridization, DNA/RNA protection assays, nucleotide sequencing, and chemical/enzymatic structural mapping/footprinting, among others. One of the most important aspects of these protocols is the use of either radioactively or nonradioactively labeled nucleic acids (DNA or RNA) as probes that speci cally hybridize with their complementary DNA or RNA strands. The quality of the probe plays an essential role in detecting speci c DNA or RNA sequences of interest. Therefore, the preparation of a probe with high speci c activity is critical in nucleic acid hybridization.1 The present chapter describes in detail reliable methods for the labeling of DNA and RNA.2-6 These methods are well established and have been routinely used in our laboratory.
