dnas Protocols

Category: Transfection Protocols: Calcium Phosphate Transfection Protocols

Calcium phosphate forms an insoluble precipitate with DNA, which attaches to the cell surface and is taken into the cells by endocytosis. The protocol is easily adapted for use with other types of cells, both adherent and nonadherent. This protocol is a modified version of a method published by Jordan et al. (1996) who rigorously optimized calcium-phosphate-based transfection methods for Chinese hamster ovary cells and the 293 line of human embryonic kidney cells. - [Read Calcium-phosphate-mediated Transfection of Eukaryotic Cells with Plasmid DNAs]

Category: PCR Protocols: PCR Cloning Protocols

This method of direct cloning takes advantage of the unpaired adenosyl residue added to the 3' terminus of amplified DNAs by Taq and other thermostable polymerases. - [Read Cloning PCR Products into T Vectors Protocol]

Category: Genetics and Genomics: Cancer Genetics Protocols: Single Strand Conformational Polymorphism(SSCP) Protocols

Single-strand conformational polymorphism (SSCP), one of several methods used to scan segments of DNA for mutations, exploits the electrophoretic differences in mobilities between single-stranded mutant and wild-type DNAs. - [Read Detection of Mutations by Single-strand Conformational Polymorphism Protocol]

Category: Genetics and Genomics: Genotyping Protocols: Mutation Detection Protocols

The goal of this method is to identify transcriptionally active genes in cloned segments of genomic DNA. The protocol uses hybridization and affinity purification to recover biotin-labeled cDNAs that bind to a 500-kb segment of human DNA cloned in a BAC vector. However, the method can be easily adapted to other clones of genomic DNAs cloned in high-capacity vectors. - [Read Direct Selection of cDNAs with Large Genomic DNA Clones Protocol]

Category: DNA Microarray Protocols

This protocol describes the steps required to produce a cDNA microarray. Gene-specific DNA is produced by PCR amplification of purified template plasmid DNAs from cloned ESTs. The PCR product is purified by ethanol precipitation, thoroughly resuspended in - [Read Fabrication Protocol for DNA Microarrays]

Category: Nucleic Acid Detection Protocols

Protocol describes the quantitation of DNA using Hoechst 33258, a fluorescent dye that binds to double-stranded DNA.  Fluorometry is simple and more sensitive than spectrophotometry, and allows the detection of nanogram quantities of DNA.  The assay can only be used to measure the concentration of DNAs whose sizes exceed ~1 kb, as Hoechst 33258 binds poorly to smaller DNA fragments. - [Read Fluorometric Quantitation of DNA Using Hoechst 33258 Protocol]

Category: PCR Protocols

Method describes how to modify the termini of PCR products by introducing restriction sites and other features.  To reduce the chance of contamination with exogenous DNAs, prepare and use a special set of reagents and solutions for PCR only.  Bake all glassware for 6 hours at 150°C and autoclave all plasticware. - [Read Genetic Engineering with PCR Protocol]

Category: PCR Protocols: PCR Optimization

Method describes how to modify the termini of PCR products by introducing restriction sites and other features.  To reduce the chance of contamination with exogenous DNAs, prepare and use a special set of reagents and solutions for PCR only.  Bake all glassware for 6 hours at 150°C and autoclave all plasticware. - [Read Genetic Engineering with PCR Protocol]

Category: Viral Culture and Isolation Protocols: Viral Culture Protocols

Most manipulations with M13, including preparations of viral stocks and isolation of single- and double-stranded DNAs, begin with small-scale liquid cultures that are infected with an M13 plaque, picked from an agar plate. - [Read Growing Bacteriophage M13 in Liquid Culture Protocol]

Category: Yeast Protocols: Yeast Genetics Protocols: YACs Protocols

Protocol describes methods for isolation of DNA from a strain of S. cerevisiae carrying a recombinant YAC. Because the linear YAC DNAs are sensitive to shearing forces, pipettes with wide-bore tips should be used to transfer DNAs. The method is suitable for preparing DNA that will be used for agarose gel electrophoresis, Southern blotting, subcloning, genomic library construction, PCR, or other methods that do not require intact high-molecular-weight DNA. - [Read Growth of S. cerevisiae and Preparation of DNA Protocol]

Category: BACs Bacterial Artificial Chromosome Protocols

BAC DNAs are prepared from 5-ml cultures of BAC-transformed cells by a modification of the standard alkaline lysis method (Preparation of Plasmid DNA by Alkaline Lysis with SDS: Minipreparation). The yield typically varies between 0.1 and 0.4 µg of BAC DNA. - [Read Isolation of BAC DNA from Small-scale Cultures Protocol]

Category: Nucleic Acid Electrophoresis Protocols: DNA Electrophoresis Protocols: DNA Electrophoresis in Polyacrylamide Gels Protocols

The "crush and soak" method, which works best for DNAs <1 kb in size, can be used to recover both singleand double-stranded DNAs from polyacrylamide gels.  The yield of eluted DNA varies from <30% to >90% depending on the size of the DNA fragment. - [Read Isolation of DNA Fragments from Polyacrylamide Gels by the Crush and Soak Method Protocol]

Category: Cloning Protocols

Protocol for ligating plasmid and target DNAs in low-melting-temperature agarose. Ligation in low-melting-temperature agarose is much less efficient than ligation with purified DNA in free solution and requires a large amount of DNA ligase. The method is used chiefly for rapid subcloning of segments of DNA in dephosphorylated vectors and assembling recombinant constructs. - [Read Ligating Plasmid and Target DNAs in Low-melting-temperature Agarose Protocol]

Category: PCR Protocols: Standard PCR Protocol

Protocol can be used to amplify DNA up to 25 kb in length.  To reduce the chance of contamination with exogenous DNAs, prepare and use a special set of reagents and solutions for PCR only.  Bake all glassware for 6 hours at 150°C and autoclave all plasticware. - [Read Long PCR Protocol]

Category: Nucleic Acid Electrophoresis Protocols: Pulsed Field Gel Electrophoresis Protocols

Protocol for preparation of DNA for pulsed-field gel electrophoresis: isolation of DNA from mammalian cells and tissues. Genomic DNAs from mammalian cells are prepared for pulsed-field gel electrophoresis by lysing cells in situ in an agarose plug.  Following digestion with an appropriate restriction enzyme, the plug is loaded directly into the well of a pulsed-field gel or it can be melted before loading. - [Read Preparation of DNA for Pulsed-field Gel Electrophoresis: Isolation of DNA from Mammalian Cells]

Category: Reporter Gene Assays: GFP Assay Protocols

In preparation for FLIM-FRET analysis, the appropriate donor and acceptor components must be introduced into live or fixed cells. The method of introduction depends on the nature of the components and the state of the cells. For example, plasmid DNAs encoding a protein of interest fused to a variant of GFP may be introduced into live cells by transfection or microinjection, whereas labeled antibodies are delivered by microinjection. - [Read Probing Protein Interactions Using GFP and FRET Protocol]

Category: Nucleic Acid Electrophoresis Protocols: Pulsed Field Gel Electrophoresis Protocols

Protocol for pulsed-field gel electrophoresis via contour-clamped homogeneous electric field gels. In CHEF gels, the electric field is generated from multiple electrodes, arranged in a square of hexagonal contour around the horizontal gel and clamped to predetermined potentials.  Using a combination of low field strengths, low concentrations of aragose, long switching intervals, and extended periods of electrophoresis, DNAs up to 5000 kb can be resolved. - [Read Pulsed-field Gel Electrophoresis via Contour-clamped Homogeneous Electric Field Gels Protocol]

Category: Nucleic Acid Purification Protocols: DNA Isolation Protocols: DNA Plasmid Preps Protocols

A solution containing plasmid DNA, saturating amounts of ethidium bromide, and CsCl (44% w/v) is layered between two solutions of lesser (35% w/v CsCl) and greater density (59% w/v CsCl).  During centrifugation to equilibrium, the closed circular plasmid DNA and linear DNAs form bands at different densities. - [Read Purification of Closed Circular DNA by Equilibrium Centrifugation in CsCl-Ethidium Bromide Gradient]

Category: Nucleic Acid Purification Protocols: DNA Isolation Protocols: DNA Plasmid Preps Protocols

Solutions containing plasmid DNA are adjusted to a density of 1.55 g/ml with solid CsCl.  The intercalating dye, ethidium bromide, which binds differentially to closed circular and linear DNAs, is then added to a concentration of 200 mu;g/ml.  During centrifugation to equilibrium, the closed circular DNA and linear DNAs form bands at different densities. - [Read Purification of Closed Circular DNA by Equilibrium Centrifugation in CsCl-Ethidium Bromide Gradients]

Category: PCR Protocols: Quantitative PCR Protocols

Protocol that uses the polymerase chain reaction (PCR) to quantitate the numbers of a particular DNA sequence, from 1 to 20,000 molecules per sample.  In addition, it helps assess the presence of contaminating sequences, which can seriously affect the outcome of the procedure. - [Read Quantitation of Rare DNAs by PCR Protocol]

Category: Viral Culture and Isolation Protocols: Viral Culture Protocols

This protocol is used to purify small amounts of recombinant DNAs cloned in robust strains of bacteriophage {lambda} such as {lambda}gt10, {lambda}gt11, {lambda}ZAP, or ZipLox. The DNAs are suitable for use as substrates for restriction enzymes and templates for DNA and RNA polymerases. - [Read Rapid Analysis of Bacteriophage {lambda} Isolates: Purification of {lambda} DNA from Liquid Cultures]

Category: PCR Protocols: PCR Cloning Protocols

In this protocol sequences cloned in standard bacteriophage or plasmid vectors are amplified in PCRs containing primers targeted to flanking vector sequences.  The amplified fragments can be analyzed by gel electrophoresis, DNA sequencing, and/or restriction mapping.  Many colonies or plaques can be assayed simultaneously. - [Read Rapid Characterization of DNAs Cloned in Prokaryotic Vectors Protocol]

Category: Nucleic Acid Electrophoresis Protocols: DNA Electrophoresis Protocols: DNA Electrophoresis in Agarose Gels Protocols

A messy but reliable technique that works well for DNAs ranging in size from 200 bp to >50 kb. - [Read Recovery of DNA from Agarose and Polyacrylamide Gels: Electroelution into Dialysis Bags Protocol]

Category: Nucleic Acid Electrophoresis Protocols: DNA Electrophoresis Protocols: DNA Electrophoresis in Polyacrylamide Gels Protocols

A messy but reliable technique that works well for DNAs ranging in size from 200 bp to >50 kb. - [Read Recovery of DNA from Agarose and Polyacrylamide Gels: Electroelution into Dialysis Bags Protocol]

Category: Nucleic Acid Electrophoresis Protocols: DNA Electrophoresis Protocols: DNA Electrophoresis in Agarose Gels Protocols

A fragment of gel containing a band of DNA is excised and digested with agarase, which hydrolyzes the polymer to disaccharide subunits.  The released DNA is then purified by phenol extraction and ethanol precipitation.  The method works well for DNAs ranging in size from <5 kb to >20 kb. - [Read Recovery of DNA from Low-melting-temperature Agarose Gels: Enzymatic Digestion with Agarase Protocol]