cDNA Library Construction Protocols

Protocol for cloning genes from a phage library. Includes: Titer and plate out phage; Lift plaques onto filters and prepare them for screening; Make a probe; Hybridize the probe to the filters; Wash the filters and expose to film; Purify putative plaques; Excise plasmid from the desired phage. - [Read Clone Genes From a Phage Library Protocol]

Shotgun sequencing of a large segment of DNA involves random fragmentation of the target region into smaller segments that are subsequently cloned into a bacteriophage M13 vector. The goal is to create a library of overlapping clones that provide at least fivefold coverage over the entire length of the target fragment. - [Read Generation of a Library of Randomly Overlapping DNA Inserts Protocol]

Information on lambda methods media and solutions. - [Read Lambda Methods Media and Solutions]

PCR can be used to identify rare DNA sequences in DNA libraries by increasing the abundance of a particular sequence. This is accomplished by subdividing the original library into pools of decreased complexity and screening each pool or group of pools for a given DNA sequence. - [Read PCR-Based Screening of DNA Libraries Protocol]

Two methods of screening pools of cloned cDNAs are discussed: transfection into mammalian cells and injection into Xenopus oocytes. - [Read Screening cDNA Libraries Constructed in Eukaryotic Expression Vectors Protocol]

An expression library constructed in a bacteriophage {lambda} vector is plated on an appropriate E. coli strain in the absence of isopropylthio-ß-D-galactoside (IPTG). After 2-4 hours, the plates are moved to 37°C (to stabilize any fusion proteins that are temperature sensitive), and filters impregnated with IPTG are laid on top of the developing plaques. - [Read Screening Expression Libraries Constructed in Bacteriophage Lambda Vectors Protocol]

Protocol for shotgun library construction. - [Read Shotgun Library Construction Protocol]

A vector that lacks inserts can significantly contaminate a DNA library. This contamination can occur either from self-ligation of single-cut vector or from uncut circular starting plasmid. - [Read Synthesis of DNA Libraries: Use of PCR to Analyze Ligation Substrates and Products]

Protocol describes the use of PCR to characterize a peptide library encoded in a plasmid vector. In this example, the library was obtained by transforming bacteria with the ligation reaction at the end of Use of PCR to Prepare a Double-Stranded DNA Library Encoding Random Peptides. - [Read Use of PCR for Quality Control of a Peptide DNA Library Protocol]

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]