Most powerful and convincing method to determine if a specific protein is phosphorylated in a physiologically relevant manner is to assay phosphorylation in situ. The procedure described involves incubating cultured cells (e.g., primary neuronal cultures or transfected cells) or tissue preparations (e.g., hippocampal slices) with [32P]orthophosphate, which is then taken up by the cells or tissues and incorporated into the γ-phosphate position of ATP. - [Read Detection of Protein Phosphorylation in Tissues and Cells Protocol]
Dnase I is used to fragment a radiolabeled target DNA in the presence and absence of a nuclear extract. A "footprint" is generated when a protein binds to the target and protects a specific segment of DNA from the nucleolytic activity of Dnase I. By comparing the electrophoretic mobility of the Dnase I cleavage products to those of a sequence ladder derived from the same DNA fragment, the position(s) of the DNA sequences recognized by DNA-binding proteins can be determined. - [Read Mapping Protein-binding Sites on DNA by Dnase I Footprinting Protocol]
Protocol for RNA labeling by in vitro transcription of DNA with DIG, Biotin or Fluorescein RNA Labeling Mix. A PCR fragment that has the appropriate promoter ligated to its 5’-ends can also serve as a transcription template. The procedure described incorporates one modified nucleotide (DIG-, Biotin-, or Fluorescein-UTP) at approximately every 20 – 25th position in the transcripts. - [Read RNA Labeling by In Vitro Transcription of DNA with DIG, Biotin or Fluorescein RNA Labeling Mix]
Single Nucleotide Primer Extension can be used for the analysis of methylation in a certain position. Treat DNA with bisulphite and then anneal a primer which ends immediately before the site of analysis. Dr. A. Gratchev Methods.info - [Read Singel Nucleotide Primer Extension (SNuPE)]
Protocol used to determine the position of molecular-weight markers and to ensure that efficient transfer of proteins to the blot has occurred, the total composition of the proteins can be determined by staining the membrane with Ponceau S (Staining Immunoblots for Total Protein Using Ponceau S) or India ink. - [Read Staining Immunoblots for Total Protein Using India Ink Protocol]
Protocol used to determine the position of molecular-weight markers and to ensure that efficient transfer of proteins to the blot has occurred, the total composition of the proteins can be determined by staining the membrane with Ponceau S . - [Read Staining Immunoblots for Total Protein Using Ponceau S Protocol]
In the routine method described in this protocol, chylomicron-free plasma is adjusted to 12% (w/v) iodixanol and the sample, essentially fills an approx 3 ml tube for a near-vertical rotor. During the centrifugation VLDL, LDL and HDL particles and also plasma proteins migrate from all parts of the sample to their final buoyant density banding position in the self-forming density gradient. - [Read Subfractionation of Low-Density Lipoprotein (LDL)]
PCR is used as a preparative tool for the synthesis of a high-complexity double-stranded DNA library. In the example presented here, a mixture of synthetic oligonucleotides is used to synthesize a random peptide NNK library, where K is either T or G. The exclusion of A and C nucleotides at the third position decreases the occurrence of stop codons but still allows codons for all 20 amino acids. - [Read Use of PCR to Prepare a Double-Stranded DNA Library Encoding Random Peptides Protocol]