Plasmids plasmid vectors

Plasmid Vectors for Facile Introduction of Passenger DNA and Selection of Recombinants. The map of a commonly used plasmid vector, pUC19 (7), is shown in Figure 2. Three parts of the vector are key to its utility. The origin sequence, oh, allows the repHcation of plasmid DNA in high copy number relative to the chromosome. A gene, amp, encoding the enzyme beta-lactamase, which hydrolyzes penicillin compounds, allows... 

Fig. 2. (a) Map of pUC19, a commonly used plasmid vector where the numbers correspond to the positions of the various restriction enzyme cuts and (b) nucleic acid composition of pUC19 from position 393 (5 -end) through position 469 (3 -end) (5,7). 

FIGURE 13.2 Foreign DNA sequences can be inserted into plasmid vectors by opening the circnlar plasmid with a restriction endonnclease. The ends of the linearized plasmid DNA are then joined with the ends of a foreign sequence, reclosing the circle to create a chimeric plasmid. 

The nucleotide sequence of a polylinker in a particular plasmid vector is... 

The plasmid vector pTEV-DHFR was used in this study. Internal ribosome entry sequence originated from tobacco etch virus (TEV) was locatai at upstream of dihydrofolate reductase (DHFR) gene. 

Herrera-Estrella L, Depicker M, Van Montagu M, Schell J (1983) Expression of chimeric genes transferred into cells using a Ti-plasmid-derived vector. Nature 303 209-213... 

DNA construct will often contain an effect gene and a selectable marker gene (such as antibiotic or herbicide resistance), both of which are bracketed by promoter and terminator sequences. A plasmid vector carries this cassette of genetic information into the plant genome by one of the above methods. 

Fig. 1 Schematic outline of procedures employed in the synthesis of a cDNA gene copy from a polyadenylated mRNA template, insertion of the cDNA into a bacterial plasmid vector by a homopolymer tailing strategy, and cloning of the recombinant plasmid in an Escherichia coli host.

One usually tries to adjust experimental conditions so that only one plasmid or phage is introduced into a single cell. When that cell replicates on a plate of nutrient agar, it will produce millions of cells until a colony becomes visible to the naked eye. If cells are sufficiently diluted before they are spread onto the plate, each colony will consist of a clone derived from a single ancestral cell. If each cell originally contained only one copy of the phage or plasmid vector, each colony will contain recombinant DNA that is homogeneous. That is, each colony will contain cloned DNA. 

Umelo-Njaka, E., Nomellini, J.F., Yim, H. and Smit, J. (2001) Development of small high-copy-number plasmid vectors for gene expression in Caulobacter crescentus. Plasmid, 46 (1), 37 46. 

Huynh, C.Q. and Zieler, H. (1999) Construction of modular and versatile plasmid vectors for the high-level expression of single or multiple genes in insects and insect cell lines. Journal of Molecular Biology, 288 (1), 13—20. 

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