PCR-based screening of YAC clones without DNA extraction

Nucleic Acids Research, 1992

We have developed a simple two-dimensional YAC pooling strategy to facilitate YAC library screening via STS and Alu-PCR approaches. The method has been implemented using the human total genomic YAC library of Olson and coworkers, and its validity tested by isolation of many chromosomes 19-and 21-specific YACs. The Alu-PCR approach is notable in that it is hybridization-based, such that PCR primer pairs do not need to be repeatedly synthesized and tested for each screening step.

IUBMB Life, 1997

Yeast is widely used in molecular biology. Heterologous expression of recombinant proteins in yeast involves screening of a large number of recombinants. We present an easy and reliable procedure for amplifying genomic DNA from freshly grown cells of the methylotrophic yeast Pichia pastoris by means of PCR without any prior DNA purification steps. This method involves a simple boiling step of whole yeast ceils in the presence of detergent, and subsequent amplification of genomic DNA using short sequencing primers in a polymerase chain reaction assay with a decreasing annealing temperature.

Genomics, 2001

We constructed representative large-insert bacterial artificial chromosome (BAC) libraries of two human pathogens (Trypanosoma brucei and Giardia lamblia) using a new hybrid vector, pTARBAC1, containing a yeast artificial chromosome (YAC) cassette (a yeast selectable marker and a centromere). The cassette allows transferring of BACs into yeast for their further modification. Furthermore, the new hybrid vector provides the opportunity to re-isolate each DNA insert without construction of a new library of random clones. Digestion of a BAC DNA by an endonuclease that has no recognition site in the vector, but which deletes most of the internal insert sequence and leaves the unique flanking sequences, converts a BAC into a TAR vector, thus allowing direct gene isolation. Cotransformation of a TAR vector and genomic DNA into yeast spheroplasts, and subsequent recombination between the TAR vector's flanking ends and a specific genomic fragment, allows rescue of the fragment as a circular YAC/BAC molecule. Here we prove a new cloning strategy by re-isolation of randomly chosen genomic fragments of different size from T. brucei cloned in BACs. We conclude that genomic regions of unicellular eukaryotes can be easily re-isolated using this technique, which provides an opportunity to study evolution of these genomes and the role of genome instability in pathogenicity. , available online at http://www.idealibrary.com on IDEAL DNA probe and PCR analysis of Sir2. A T. brucei Sir2-specific fragment (GenBank acc. no. AF102869) was labeled with [␣-32 P]dCTP by random-priming DNA synthesis [18] and used to screen the RPCI-102 T. brucei library. The posi-

YAC Protocols, 2006

We have developed a quick and low-cost genomic DNA extraction protocol from yeast cells for PCR-based applications. This method does not require any enzymes, hazardous chemicals, or extreme temperatures, and is especially powerful for simultaneous analysis of a large number of samples. DNA can be efficiently extracted from different yeast species (Kluyveromyces lactis, Hansenula polymorpha, Schizosaccharomyces pombe, Candida albicans, Pichia pastoris, and Saccharomyces cerevisiae). The protocol involves lysis of yeast colonies or cells from liquid culture in a lithium acetate (LiOAc)–SDS solution and subsequent precipitation of DNA with ethanol. Approximately 100 nanograms of total genomic DNA can be extracted from 1 × 107 cells. DNA extracted by this method is suitable for a variety of PCR-based applications (including colony PCR, real-time qPCR, and DNA sequencing) for amplification of DNA fragments of ≤3500 bp.

Nucleic Acids Research, 1995

Yeast artificial chromosomes (YACs) provide a powerful way to isolate and map large regions of genomic DNA and their use in genome analysis is now extensive. We modified a series of procedures to produce high quality shotgun libraries from small amounts of YAC DNA. Clones from several different libraries have been sequenced and analyzed for distribution, sequence integrity and degree of contamination from yeast DNA. We describe these procedures and analyses and show that sequencing at about 1-fold coverage, followed by database comparison (survey sequencing) offers a relatively quick method to determine the nature of previously uncharacterized cosmid or YAC clones.

Biotechnology Letters, 2006

A very simple and rapid method for extracting genomic DNA from Gram-negative bacteria, Gram-positive bacteria and yeasts is presented. In this method, bacteria or yeasts are lysed directly by phenol and the supernatant is extracted with chloroform to remove traces of phenol. The supernatant contains DNA that is suitable for molecular analyses, such as PCR, restriction enzyme digestion and genomic library construction. This method is reproducible and simple for the routine DNA extraction from bacteria and yeasts.

MGG Molecular & General Genetics, 1978

A procedure is described for the detection of specific DNA sequences in Saccharomyces cerevisiae. This method allows a rapid screening of a large number of yeast colonies. The yeast cells of each colony, grown on nitrocellulose filters, are converted, in situ, to protoplasts by snail enzyme, and are then lysed and their DNAs are denatured and fixed on the filter. The presence of the specific DNA sequence is detected directly on the filter by hybridization with a radioactive cRNA.

PLoS ONE, 2014

Herein, we describe a novel cloning strategy for PCR-amplified DNA which employs the type IIs restriction endonuclease BsaI to create a linearized vector with four base-long 59-overhangs, and T4 DNA polymerase treatment of the insert in presence of a single dNTP to create vector-compatible four base-long overhangs. Notably, the insert preparation does not require any restriction enzyme treatment. The BsaI sites in the vector are oriented in such a manner that upon digestion with BsaI, a stuffer sequence along with both BsaI recognition sequences is removed. The sequence of the four base-long overhangs produced by BsaI cleavage were designed to be non-palindromic, non-compatible to each other. Therefore, only ligation of an insert carrying compatible ends allows directional cloning of the insert to the vector to generate a recombinant without recreating the BsaI sites. We also developed rapid protocols for insert preparation and cloning, by which the entire process from PCR to transformation can be completed in 6-8 h and DNA fragments ranging in size from 200 to 2200 bp can be cloned with equal efficiencies. One protocol uses a single tube for insert preparation if amplification is performed using polymerases with low 39-exonuclease activity. The other protocol is compatible with any thermostable polymerase, including those with high 39-exonuclease activity, and does not significantly increase the time required for cloning. The suitability of this method for high-throughput cloning was demonstrated by cloning batches of 24 PCR products with nearly 100% efficiency. The cloning strategy is also suitable for high efficiency cloning and was used to construct large libraries comprising more than 10 8 clones/mg vector. Additionally, based on this strategy, a variety of vectors were constructed for the expression of proteins in E. coli, enabling large number of different clones to be rapidly generated.

The Japanese Journal of Human Genetics, 1991

A simple strategy for the rapid preparation of an end-specific linking-DNA probe from the YAC-human chromosome 21 DNA recombinant clone and the characterization of this single DNA probe are described. Synthetic oligodeoxynucleotide primers, based on the consensus Alu sequence, and the Sup4 DNA fragment in the YAC arms were used to amplify end-specific DNA sequences by the polymerase chain reaction (PCR) for screening of the linking YAC recombinant clones ("YAC-Alu PCR"). Nucleotide sequencing of the product of PCR from human genomic DNA in a YAC insert confirmed the boundary between the vector and the insert and the presence of the 3'-end Alu-like structure. The probe R1, prepared by "YAC-Alu PCR" amplification, was assigned to chromosome 21 by Southern hybridization of somatic cell hybrid DNAs. In situ hybridization allowed localization of the R1 DNA probe to the human chromosome 21q21-q22.1 region. Thus, this approach has significant advantages not only for isolation of a single DNA probe specific for human chromosome 21 but also for the screening of YAC linking recombinant clones for mapping of the human genome.