EMSA probe creation using ds Oligonucleotides by annealing two complementary oligos, and Klenow for probe creation. - [Read EMSA using ds Oligonucleotides]
In this procedure, synthesis of cDNA is carried out in the presence of saturating concentrations of all four dNTPs and trace amounts of a single radiolabeled dNTP. After subtraction hybridization, the enriched single-stranded cDNA is radiolabeled to high specific activity in a second synthetic reaction by extension of random oligonucleotide primers using the Klenow fragment of E. coli DNA polymerase. - [Read Radiolabeling of Subtracted cDNA Probes by Random Oligonucleotide Extension Protocol]
A synthetic oligonucleotide annealed to single-stranded DNA derived from a recombinant bacteriophage M13 or phagemid template is used to prime the synthesis of complementary radiolabeled DNA. Synthesis is catalyzed by the Klenow fragment of E. coli DNA polymerase I, which extends the annealed primer for various distances along the single-stranded template DNA. - [Read Synthesis of Single-stranded DNA Probes of Defined Length from Bacteriophage M13 Templates Protocol]
DNA microarrays are an ordered arrangement of DNA molecules complementary to genes of interest that are "spotted" by robotic equipment onto a glass slide substrate. The expression of genes in cells can be monitored with microarrays by preparing cDNA from the mRNA of cells of interest and measuring the hybridization to the microarray. This protocol describes the labeling of genomic DNA for use as a probe for hybridization to the cDNA spotted on the array.