To generate "5'-end" partial cDNA clones using classic RACE, the first-strand products are generated by reverse transcription (primer extension) from a known gene-specific primer (GSP-RT). Then, a poly(A) tail is appended using terminal deoxynucleotidyltransferase (Tdt) and dATP. Amplification is carried out using three primers. - [Read 5'-End cDNA Amplification Using Classic RACE Protocol]
The MagneSil system can selectively isolate PCR products that are more than 150-bp long from primers and primer -dimers. The technology can be used with a number of robotic workstations, including Beckman Coulter’s Biomek 2000 and FX Laboratory Automation Workstations. The procedure can also be carried out manually. Typical recovery is more than 80% for a 1-kb product with negligible carryover of primers or nucleotides. - [Read A Magnetic Particle-Based Method for Purifying PCR Products from Solution Protocol]
Protocol describes the use of PCR to screen for bacteria that carry recombinant plasmids. The PCR can be carried out using the same primers as for amplification of the cloned insert. To determine the orientation of the insert, a third, insert-specific primer that is asymmetrically distanced from the clonal insertion site can be used. - [Read Colony PCR Protocol II]
The first step in competitive RT-PCR is the synthesis and purification of the synthetic competitor. This is an RNA molecule designed to be reverse-transcribed and PCR-amplified with the same efficiency as the endogenous transcript of interest. Once the competitor molecule has been prepared, as described in this protocol, competitive PCR can be carried out. - [Read Competitive RT-PCR: Preparation of Competitor RNA Protocol]
Because sequencing reactions catalyzed by thermostable DNA polymerasessuch as Taq are carried out at elevated temperatures, problemscaused by mismatched annealing of primers or templates richin secondary structure are greatly alleviated. - [Read Dideoxy-mediated Sequencing of DNA Using Taq DNA Polymerase Protocol]
Protocol for dot and slot hybridization of purified RNA. Dot blotting of RNA is best carried out using purified preparations of RNA that are denatured with glyoxal or formaldehyde immediately before loading onto a nylon membrane through a vacuum manifold. - [Read Dot and Slot Hybridization of Purified RNA Protocol]
FPLC Protocol. The FPLC consists of a pump and a column which will withstand high pressure so separations can be carried out relatively quickly. For a detailed description there is a FPLC system handbook which is particularly useful for trouble shooting. For use of individual columns follow the "instructions" (in the green folder) which accompany each one. Sir William Dunn School of Pathology, Oxford University. - [Read FPLC Protocol]
Hybridization is carried out in conventional aqueous solvents at a temperature well below the predicted melting temperature. Nonspecific hybrids are then removed by washing at high stringency in buffers containing quaternary salts. Tetramethylammonium chloride (TMACl) is used with probes that are 14-50 nucleotides in length, whereas tetraethylammonium chloride (TEACl) is used with longer oligonucleotides. - [Read Hybridization of Oligonucleotide Probes in Aqueous Solutions Protocol]
Protocol describes, samples containing the target protein are deposited onto a polyvinyldifluoride (PVDF) membrane using a vacuum manifold. The immobilized protein is exposed to an antibody specific for the target protein, followed by an antibody that reacts with species-specific determinants carried by the primary antibody and is conjugated to horseradish peroxidase (HRP). - [Read Measuring Protein Concentration by Western Analysis Using Enhanced Chemiluminescence Detection]
Procedure generates competent cultures of E. coli that can be transformed at high frequencies (5 x 108 transformed colonies/µg of superhelical plasmid DNA). IMPORTANT All steps in this protocol should be carried out aseptically. - [Read Preparation and Transformation of Competent E. coli Protocol]
An ideal method of tissue preparation ensures both good specimen morphology and that the target molecules are in the optimum state for probe access and hybridization. DNA:DNA in situ hybridization is usually carried out on chromosome spread preparations where chromosome and nuclei are released from cells and spread on a glass microscope slide. This method yields well separated and enlarged chromosomes with good morphology which can be analyzed in transmitted light or fluorescence microscopes. - [Read Preparation of Chromosome Spreads]
Most histological studies are carried out on paraformaldehyde-fixed, paraffin-embedded tissue samples. Therefore, there is an extensive atlas of most tissues and organs prepared from these sources, and comparing the location of antigens to these data is immediately informative. The fixation and embedding procedures are harsh, however, and many antigens are not well preserved. - [Read Preparing Paraffin Tissue Sections for Immunostaining Protocol]
Recombinant proteins engineered to have a polyhistidine tail at either the carboxyl or amino terminus can easily be purified in one step by affinity chromatography on a resin carrying chelated nickel ions. Chromatography can be carried out in column or batch formats. After unbound proteins are washed away, the target protein is eluted using imidazole, which typically preserves the antigenic and functional features of the protein. - [Read Purification of Histidine-tagged Proteins by Immobilized Ni2+ Absorption Chromatography Protocol]
This protocol describes a discontinuous gradient, which resolves the mitochondria from both lighter and denser organelles. Because the centrifugation is carried out for 4 h, diffusion will create a partially continuous gradient and this probably contributes to the resolution of the mitochondria from the lighter lysosomes. - [Read Purification of Mammalian Liver Mitochondria by Flotation Through a Pre-formed Discontinuous Iodixan]
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]
Plaques formed by M13 bacteriophages or bacterial colonies transformed by plasmids carrying specific mutations can be detected by hybridization, using a radiolabeled oligonucleotide that forms a perfect duplex with the mutant sequence. Hybridization is carried out under conditions of low stringency that allow the radiolabeled oligonucleotide to anneal to both mutant and wild-type DNAs. - [Read Screening Recombinant Clones for Site-directed Mutagenesis by Hybridization to Radiolabeled Oligos]
Slide Preparation for Manual Microdissection for Subsequent DNA, RNA, and Protein Analysis. Manual microdissection and subsequent molecular analysis can be carried out on slides stained using standard hematoxylin and eosin methods. However, if cell types that are (or are not) expressing a specific protein are required for a study, then more advanced slide preparation methods such as Immuno-LCM may be utilized. - [Read Slide Preparation for Manual Microdissection Protocol]
Protocol for southern hybridization of radiolabeled probes to nucleic acids immobilized on membranes. Protocol describes how to carry out Southern hybridizations at high stringency in phosphate-SDS buffers. Although a wide variety of formats are available, most Southern hybridizations are carried out in heat-sealable bags, roller bottles, or plastic boxes. - [Read Southern Hybridization of Radiolabeled Probes to Nucleic Acids Immobilized on Membranes Protocol]
In Vitro Translated Xenopus Mos Kinase Assay Protocol. In response to progesterone, immature Xenopus oocytes mature to eggs that can be fertilized. The Mos protein kinase is essential for oocyte maturation, most likely due to its ability to activate the MAP kinase cascade. This MAP kinase cascade eventually leads to the activation of Cdc2/cyclin B and entry into M phase. In this protocol, tagged Mos kinase is translated in vitro, immunopurified, and used in a kinase assay.