cloning vector

(noun)

A cloning vector is a small piece of DNA, taken from a virus, a plasmid, or the cell of a higher organism, into which a foreign DNA fragment can be inserted.

Related Terms

Examples of cloning vector in the following topics:

  • Hosts for Cloning Vectors

    • The majority of molecular cloning experiments begin with a laboratory strain of the bacterium E. coli (Escherichia coli) as the host.
    • A very large number of host organisms and molecular cloning vectors are in use, but the great majority of molecular cloning experiments begin with a laboratory strain of the bacterium E. coli (Escherichia coli) and a plasmid cloning vector.
    • If the DNA to be cloned is exceptionally large (hundreds of thousands to millions of base pairs), then a bacterial artificial chromosome or yeast artificial chromosome vector is often chosen.
    • Specialized applications may call for specialized host-vector systems.
    • In practice, however, specialized molecular cloning experiments usually begin with cloning into a bacterial plasmid, followed by subcloning into a specialized vector.

  • Plasmids as Cloning Vectors

    • Plasmids can be used as cloning vectors, allowing the insertion of exogenous DNA into a bacterial target.
    • All engineered vectors have an origin of replication, a multi-cloning site, and a selectable marker.
    • Modern plasmids generally have many more features, notably a "multiple cloning site"—with nucleotide overhangs for insertion of an insert—and multiple restriction enzyme consensus sites on either side of the insert.
    • Expression vectors require translation of the vector's insert, thus requiring more components than simpler transcription-only vectors.
    • The pGEX-3x plasmid is a popular cloning vector.

  • Obtaining DNA

    • Although a very large number of host organisms and molecular cloning vectors are used, the great majority of molecular cloning experiments begin with a laboratory strain of the bacterium E. coli (Escherichia coli) and a plasmid cloning vector.
    • The cloning vector is treated with a restriction endonuclease to cleave the DNA at the site where foreign DNA will be inserted.
    • Most modern vectors contain a variety of convenient cleavage sites that are unique within the vector molecule (so that the vector can only be cleaved at a single site) and are not located within the gene of interest to be cloned.
    • Cells harboring the cloning vector will survive when exposed to the antibiotic, while those that have failed to take up cloning vector will die.
    • The former can therefore be amplified and screened for the presence of the gene of interest in the cloning vector by restriction digest analysis.

  • Recombinant DNA Technology

    • Although a very large number of host organisms and molecular cloning vectors are in use, the great majority of molecular cloning experiments begin with a laboratory strain of the bacterium E. coli (Escherichia coli) and a plasmid cloning vector.
    • The cloning vector is treated with a restriction endonuclease to cleave the DNA at the site where foreign DNA will be inserted.
    • For cloning of genomic DNA, the DNA to be cloned is extracted from the organism of interest.
    • Modern bacterial cloning vectors (e.g. pUC19) use the blue-white screening system to distinguish colonies (clones) of transgenic cells from those that contain the parental vector.
    • The blue-white screen is a screening technique that allows for the detection of successful ligations in vector-based gene cloning.

  • Shuttle Vectors and Expression Vectors

    • Therefore, to make the purification process easy, the cloned gene should have a tag.
    • Cloning vectors, which are very similar to expression vectors, involve the same process of introducing a new gene into a plasmid, but the plasmid is then added into bacteria for replication purposes.
    • In general, DNA vectors that are used in many molecular-biology gene-cloning experiments need not result in the expression of a protein.
    • The pGEX-3x plasmid is a popular cloning vector.
    • Please note the presence of a multiple cloning site, a promoter, a repressor, and a selectable marker.

  • Vectors for Genomic Cloning and Sequencing

    • The four major types of vectors are plasmids, viral vectors, cosmids, and artificial chromosomes.
    • Simpler vectors called transcription vectors are only capable of being transcribed but not translated: they can be replicated in a target cell but not expressed, unlike expression vectors.
    • Transcription vectors are used to amplify their insert.
    • Modern plasmids generally have many more features, notably including a "multiple cloning site" which includes nucleotide overhangs for insertion of an insert, and multiple restriction enzyme consensus sites to either side of the insert.
    • The vectors can be extracted from the bacteria, and the multiple cloning sites can be cut by restriction enzymes to excise the hundredfold or thousandfold amplified insert.

  • Production of Vaccines, Antibiotics, and Hormones

    • Modern techniques use the genes of microorganisms cloned into vectors to mass produce the desired antigen.
    • Genes cloned from the influenza virus have been used to combat the constantly-changing strains of this virus.
    • The HGH gene was cloned from a cDNA library and inserted into E. coli cells by cloning it into a bacterial vector.

  • Molecular and Cellular Cloning

    • In general, the word "cloning" means the creation of a perfect replica; however, in biology, the re-creation of a whole organism is referred to as "reproductive cloning."
    • A plasmid (also called a vector) is a small circular DNA molecule that replicates independently of the chromosomal DNA.
    • Plasmids have been repurposed and engineered as vectors for molecular cloning and the large-scale production of important reagents such as insulin and human growth hormone.
    • An important feature of plasmid vectors is the ease with which a foreign DNA fragment can be introduced via the multiple cloning site (MCS).
    • The recombinant DNA may need to be moved into a different vector (or host) that is better designed for gene expression.

  • Genetic Engineering

    • In genetic engineering, an organism's genotype is altered using recombinant DNA, created by molecular cloning, to modify an organism's DNA.
    • Recombinant DNA technology, or DNA cloning, is the process of transferring a DNA fragment of interest from one organism to a self-replicating genetic element, such as a bacteria plasmid, which is called a vector.
    • The addition of foreign DNA in the form of recombinant DNA vectors generated by molecular cloning is the most common method of genetic engineering.
    • Gene targeting is the use of recombinant DNA vectors to alter the expression of a particular gene, either by introducing mutations in a gene, or by eliminating the expression of a certain gene by deleting a part or all of the gene sequence from the genome of an organism.

  • Selection

    • Artificial selection is widely used in the field of microbial genetics, especially molecular cloning.
    • Gene cloning and gene/protein tagging is also common.
    • In a conventional molecular cloning experiment, the DNA to be cloned is obtained from an organism of interest.
    • Subsequently, these fragments are then combined with vector DNA to generate recombinant DNA molecules.
    • Cells harboring the vector will survive when exposed to the antibiotic, while those that fail to take up vector sequences die.