It is possible that some cell lines have lost the ability to perform RNAi or that cells derived from certain tissues do not support RNAi. This reporter assay, for RNAi in mammalian cells, can be used to establish whether the cells under study are susceptible to RNAi. - [Read Cotransfection of Luciferase Reporter Plasmids with siRNA Duplexes Protocol]
Cell fractionation of cellular components using Percoll a synthetic, colloidal solution of polyvinylpyrrolidone coated silica, specifically designed for sedimentation centrifugation. Percoll becomes a simple matter to establish a linear density gradient. Organelle separations are much easier to accomplish on Percoll density gradients than on sucrose gradients. - [Read Equilibrium Density Gradient Percoll Protocol]
Pilot ligations and packaging reactions are used to establish the amounts of fragmented genomic DNA and bacteriophage {lambda} arms that yield the maximum number of recombinants. Additional ligation and packaging reactions may then be set up to yield a comprehensive library of genomic DNA. - [Read Ligation of Bacteriophage lambda Arms to Fragments of Foreign Genomic DNA Protocol]
Protocol is used to establish conditions for restriction enzyme digestion of eukaryotic genomic DNA that will generate fragments of a size appropriate for construction of genomic libraries. To construct a genomic library, the average length of the starting genomic DNA should be at least eight times the capacity of the vector. - [Read Partial Digestion of Eukaryotic DNA for Use in Genomic Libraries: Pilot Reactions Protocol]