The pGreen plasmids are vectors for plant transformation. They were first described in 2000 as components of a novel T-DNA binary system. [1] The supporting web page [2] provides supplementary information and ongoing support to researchers to request their plasmid resources. As these plasmids have been taken up by the research community, the plasmids have been developed, expanding the resources available to the community.
Researchers are encouraged to contribute to this research community by submitting their vector sequence to genbank and providing a description of the plasmid on the site.
pGreen is the original pGreen plasmid. [3] pGreenII features plasmid backbone modification to improve plasmid stability. [4]
pGreenII 0000: minimal T-DNA with Left and Right border, lacZ gene for blue/white selection during cloning multiple cloning site derived from pBluescript. [5]
pGreenII 62-SK: derived from pGreenII 0000, the LacZ blue/white cloning selection has been replaced with a 35S-MCS-CaMV cassette that allows the insertion of a gene of interest into a 35S over-expression cassette. The multiple cloning site (MCS) is derived from pBluescript. [6] [7]
pGreenII 0029: derived from pGreenII 0000, a nos-kan cassette has been inserted into the HpaI site of the Left Border, providing resistance to kanamycin during plant transformation selection. [8]
pGreenII 0029 62-SK: derived from pGreenII 0029, the LacZ blue/white cloning selection has been replaced with a 35S-MCS-CaMV cassette that allows the insertion of a gene of interest into a 35S over-expression cassette. The MCS is derived from pBluescript. [9]
pGreenII 0179: derived from pGreenII 0000, a 35S-hyg cassette has been inserted into the HpaI site of the Left Border, providing resistance to hygromycin during plant transformation selection. [10]
pGreenII 0229: derived from pGreenII 0000, a nos-bar cassette has been inserted into the HpaI site of the Left Border, providing resistance to bialaphos or phosphinothricin during plant transformation selection. [11] [12]
pGreenII 0229 62-SK: derived from pGreenII 0229, the LacZ blue/white cloning selection has been replaced with a 35S-MCS-CaMV cassette that allows the insertion of a gene of interest into a 35S over-expression cassette. The MCS is derived from pBluescript. [13]
This is the helper plasmid that provides the replicase function for the pSa replication origin of pGreen. pSoup is tetracyclin resistant and a complementary incompatibility group such that it can co-exist with pGreen in the Agrobacterium cell.
pSoup: the original help plasmid for pGreen. pGreen will not replicate in Agrobacterium if it is not present. [14]
A cloning vector is a small piece of DNA that can be stably maintained in an organism, and into which a foreign DNA fragment can be inserted for cloning purposes. The cloning vector may be DNA taken from a virus, the cell of a higher organism, or it may be the plasmid of a bacterium. The vector contains features that allow for the convenient insertion of a DNA fragment into the vector or its removal from the vector, for example through the presence of restriction sites. The vector and the foreign DNA may be treated with a restriction enzyme that cuts the DNA, and DNA fragments thus generated contain either blunt ends or overhangs known as sticky ends, and vector DNA and foreign DNA with compatible ends can then be joined by molecular ligation. After a DNA fragment has been cloned into a cloning vector, it may be further subcloned into another vector designed for more specific use.
Yeast artificial chromosomes (YACs) are genetically engineered chromosomes derived from the DNA of the yeast, Saccharomyces cerevisiae, which is then ligated into a bacterial plasmid. By inserting large fragments of DNA, from 100–1000 kb, the inserted sequences can be cloned and physically mapped using a process called chromosome walking. This is the process that was initially used for the Human Genome Project, however due to stability issues, YACs were abandoned for the use of bacterial artificial chromosome
An expression vector, otherwise known as an expression construct, is usually a plasmid or virus designed for gene expression in cells. The vector is used to introduce a specific gene into a target cell, and can commandeer the cell's mechanism for protein synthesis to produce the protein encoded by the gene. Expression vectors are the basic tools in biotechnology for the production of proteins.
Agrobacterium is a genus of Gram-negative bacteria established by H. J. Conn that uses horizontal gene transfer to cause tumors in plants. Agrobacterium tumefaciens is the most commonly studied species in this genus. Agrobacterium is well known for its ability to transfer DNA between itself and plants, and for this reason it has become an important tool for genetic engineering.
The transfer DNA is the transferred DNA of the tumor-inducing (Ti) plasmid of some species of bacteria such as Agrobacterium tumefaciens and Agrobacterium rhizogenes . The T-DNA is transferred from bacterium into the host plant's nuclear DNA genome. The capability of this specialized tumor-inducing (Ti) plasmid is attributed to two essential regions required for DNA transfer to the host cell. The T-DNA is bordered by 25-base-pair repeats on each end. Transfer is initiated at the right border and terminated at the left border and requires the vir genes of the Ti plasmid.
A cosmid is a type of hybrid plasmid that contains a Lambda phage cos sequence. Often used as cloning vectors in genetic engineering, cosmids can be used to build genomic libraries. They were first described by Collins and Hohn in 1978. Cosmids can contain 37 to 52 kb of DNA, limits based on the normal bacteriophage packaging size. They can replicate as plasmids if they have a suitable origin of replication (ori): for example SV40 ori in mammalian cells, ColE1 ori for double-stranded DNA replication, or f1 ori for single-stranded DNA replication in prokaryotes. They frequently also contain a gene for selection such as antibiotic resistance, so that the transformed cells can be identified by plating on a medium containing the antibiotic. Those cells which did not take up the cosmid would be unable to grow.
A tumour inducing (Ti) plasmid is a plasmid found in pathogenic species of Agrobacterium, including A. tumefaciens, A. rhizogenes, A. rubi and A. vitis.
A multiple cloning site (MCS), also called a polylinker, is a short segment of DNA which contains many restriction sites - a standard feature of engineered plasmids. Restriction sites within an MCS are typically unique, occurring only once within a given plasmid. The purpose of an MCS in a plasmid is to allow a piece of DNA to be inserted into that region.
pBR322 is a plasmid and was one of the first widely used E. coli cloning vectors. Created in 1977 in the laboratory of Herbert Boyer at the University of California, San Francisco, it was named after Francisco Bolivar Zapata, the postdoctoral researcher and Raymond L. Rodriguez. The p stands for "plasmid," and BR for "Bolivar" and "Rodriguez."
X-gal is an organic compound consisting of galactose linked to a substituted indole. The compound was synthesized by Jerome Horwitz and collaborators in 1964. The formal chemical name is often shortened to less accurate but also less cumbersome phrases such as bromochloroindoxyl galactoside. The X from indoxyl may be the source of the X in the X-gal contraction. X-gal is often used in molecular biology to test for the presence of an enzyme, β-galactosidase, in the place of its usual target, a β-galactoside. It is also used to detect activity of this enzyme in histochemistry and bacteriology. X-gal is one of many indoxyl glycosides and esters that yield insoluble blue compounds similar to indigo dye as a result of enzyme-catalyzed hydrolysis.
In genetics, Flp-FRT recombination is a site-directed recombination technology, increasingly used to manipulate an organism's DNA under controlled conditions in vivo. It is analogous to Cre-lox recombination but involves the recombination of sequences between short flippase recognition target (FRT) sites by the recombinase flippase (Flp) derived from the 2 μ plasmid of baker's yeast Saccharomyces cerevisiae.
The blue–white screen is a screening technique that allows for the rapid and convenient detection of recombinant bacteria in vector-based molecular cloning experiments. This method of screening is usually performed using a suitable bacterial strain, but other organisms such as yeast may also be used. DNA of transformation is ligated into a vector. The vector is then inserted into a competent host cell viable for transformation, which are then grown in the presence of X-gal. Cells transformed with vectors containing recombinant DNA will produce white colonies; cells transformed with non-recombinant plasmids grow into blue colonies.
Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells. Gene delivery must reach the genome of the host cell to induce gene expression. Successful gene delivery requires the foreign gene delivery to remain stable within the host cell and can either integrate into the genome or replicate independently of it. This requires foreign DNA to be synthesized as part of a vector, which is designed to enter the desired host cell and deliver the transgene to that cell's genome. Vectors utilized as the method for gene delivery can be divided into two categories, recombinant viruses and synthetic vectors.
Plant transformation vectors are plasmids that have been specifically designed to facilitate the generation of transgenic plants. The most commonly used plant transformation vectors are T-DNA binary vectors and are often replicated in both E. coli, a common lab bacterium, and Agrobacterium tumefaciens, a plant-virulent bacterium used to insert the recombinant DNA into plants.
A transfer DNA (T-DNA) binary system is a pair of plasmids consisting of a T-DNA binary vector and a virhelper plasmid. The two plasmids are used together to produce genetically modified plants. They are artificial vectors that have been derived from the naturally occurring Ti plasmid found in bacterial species of the genus Agrobacterium, such as A. tumefaciens. The binary vector is a shuttle vector, so-called because it is able to replicate in multiple hosts.
In molecular cloning, a vector is any particle used as a vehicle to artificially carry a foreign nucleic sequence – usually DNA – into another cell, where it can be replicated and/or expressed. A vector containing foreign DNA is termed recombinant DNA. The four major types of vectors are plasmids, viral vectors, cosmids, and artificial chromosomes. Of these, the most commonly used vectors are plasmids. Common to all engineered vectors are an origin of replication, a multicloning site, and a selectable marker.
pUC19 is one of a series of plasmid cloning vectors designed by Joachim Messing and co-workers. The designation "pUC" is derived from the classical "p" prefix and the abbreviation for the University of California, where early work on the plasmid series had been conducted. The pUC plasmids are all circular double stranded DNA about 2700 base pairs in length. The pUC plasmids are some of the most widely used cloning vectors. This is in part because cells that have successfully been transformed can be easily distinguished from those that have not based on color differences of colonies. pUC18 is similar to pUC19, but the MCS region is reversed.
Bialaphos is a natural herbicide produced by the bacteria Streptomyces hygroscopicus and Streptomyces viridochromogenes. It is also known by the ISO common name bilanafos. Bialaphos is a protoxin and nontoxic as is. When it is metabolized by a plant, the glutamic acid analog glufosinate is released which inhibits glutamine synthetase. This results in the accumulation of ammonium and disruption of primary metabolism.
The G-less cassette transcription assay is a method used in molecular biology to determine promoter strength in vitro. The technique involves quantification of an mRNA product with the use of a plasmid. The G-less cassette is part of a pre-constructed vector, usually containing a multiple cloning site (MCS) upstream of the cassette. For this reason, promoters of interest can be inserted directly into the MCS to ultimately measure the accuracy and efficiency of a promoter in recruiting transcription machinery.
Golden Gate Cloning or Golden Gate assembly is a molecular cloning method that allows a researcher to simultaneously and directionally assemble multiple DNA fragments into a single piece using Type IIS restriction enzymes and T4 DNA ligase. This assembly is performed in vitro. Most commonly used Type IIS enzymes include BsaI, BsmBI, and BbsI.