C Aslanidis

Bio: C Aslanidis is an academic researcher from Lawrence Livermore National Laboratory. The author has contributed to research in topics: Multiple cloning site & Restriction enzyme. The author has an hindex of 1, co-authored 1 publications receiving 1107 citations.

Ligation-independent cloning of PCR products (LIC-PCR)

Abstract: A new procedure has been developed for the efficient cloning of complex PCR mixtures, resulting in libraries exclusively consisting of recombinant clones. Recombinants are generated between PCR products and a PCR-amplified plasmid vector. The procedure does not require the use of restriction enzymes, T4 DNA ligase or alkaline phosphatase. The 5'-ends of the primers used to generate the cloneable PCR fragments contain an additional 12 nucleotide (nt) sequence lacking dCMP. As a result, the amplification products include 12-nt sequences lacking dGMP at their 3'-ends. The 3'-terminal sequence can be removed by the action of the (3'----5') exonuclease activity of T4 DNA polymerase in the presence of dGTP, leading to fragments with 5'-extending single-stranded (ss) tails of a defined sequence and length. Similarly, the entire plasmid vector is amplified with primers homologous to sequences in the multiple cloning site. The vector oligos have additional 12-nt tails complementary to the tails used for fragment amplification, permitting the creation of ss-ends with T4 DNA polymerase in the presence of dCTP. Circularization can occur between vector molecules and PCR fragments as mediated by the 12-nt cohesive ends, but not in mixtures lacking insert fragments. The resulting circular recombinant molecules do not require in vitro ligation for efficient bacterial transformation. We have applied the procedure for the cloning of inter-ALU fragments from hybrid cell-lines and human cosmid clones.

Enzymatic assembly of DNA molecules up to several hundred kilobases

Abstract: We describe an isothermal, single-reaction method for assembling multiple overlapping DNA molecules by the concerted action of a 5' exonuclease, a DNA polymerase and a DNA ligase. First we recessed DNA fragments, yielding single-stranded DNA overhangs that specifically annealed, and then covalently joined them. This assembly method can be used to seamlessly construct synthetic and natural genes, genetic pathways and entire genomes, and could be a useful molecular engineering tool.

Determination of microbial diversity in environmental samples: pitfalls of PCR‐based rRNA analysis

Abstract: After nearly 10 years of PCR-based analysis of prokaryotic small-subunit ribosomal RNAs for ecological studies it seems necessary to summarize reported pitfalls of this approach which will most likely lead to an erroneous description on the microbial diversity of a given habitat. The following article will cover specific aspects of sample collection, cell lysis, nucleic acid extraction, PCR amplification, separation of amplified DNA, application of nucleic probes and data analysis.

Construction of T-vectors, a rapid and general system for direct cloning of unmodified PCR products.

Abstract: Although the polymerase chain reaction (1,2) (PCR) can be used to produce a large amount of a specific DNA from a complex source, cloning the PCR products has not proven to be straightforward. Restriction endonuclease sites are often incorporated into the oligonucleotide primers used for amplification, so that cleavage of the product will create sticky ends that can theoretically be ligated to an equivalently cut vector (3). Unfortunately, many restriction endonucleases fail to cleave when their recognition sequences are located within a few base pairs of the end of a DNA fragment (4, 5). Ligation-independent PCR cloning schemes (6, 7, 8) involve the addition of at least 12 bases to the 5' end of the primer, which can increase the cost of synthesis substantially when done routinely. Attempts to clone PCR products as blunt-ended fragments have been very inefficient, due to the template-independent terminal transferase activity of Taq polymerase, which results in the addition of a single nucleotide at the 3' end of the fragment (9, 10). This nucleotide is almost exclusively an adenosine, due to the strong preference of the polymerase for dATP (9). Thus, cloning the products as blunt-ended fragments requires enzymatic processing to remove of the 3' overhang using an enzyme with 3' to 5' exonuclease activity (11).

Recent advances in the polymerase chain reaction

Abstract: The polymerase chain reaction (PCR) has dramatically altered how molecular studies are conducted as well as what questions can be asked. In addition to simplifying molecular tasks typically carried out with the use of recombinant DNA technology, PCR has allowed a spectrum of advances ranging from the identification of novel genes and pathogens to the quantitation of characterized nucleotide sequences. PCR can provide insights into the intricacies of single cells as well as the evolution of species. Some recent developments in instrumentation, methodology, and applications of the PCR are presented in this review.

Harnessing homologous recombination in vitro to generate recombinant DNA via SLIC

Abstract: We describe a new cloning method, sequence and ligation–independent cloning (SLIC), which allows the assembly of multiple DNA fragments in a single reaction using in vitro homologous recombination and single-strand annealing. SLIC mimics in vivo homologous recombination by relying on exonuclease-generated ssDNA overhangs in insert and vector fragments, and the assembly of these fragments by recombination in vitro. SLIC inserts can also be prepared by incomplete PCR (iPCR) or mixed PCR. SLIC allows efficient and reproducible assembly of recombinant DNA with as many as 5 and 10 fragments simultaneously. SLIC circumvents the sequence requirements of traditional methods and functions much more efficiently at very low DNA concentrations when combined with RecA to catalyze homologous recombination. This flexibility allows much greater versatility in the generation of recombinant DNA for the purposes of synthetic biology.