⇒ Recombinant DNA Technology
⇒ Restriction Endonucleases
⇒ Host Cells
After a desired segment of DNA is cut away from the donor's genome with
restriction endonucleases, it is ligated into a vector DNA molecule, usually
a plasmid or a bacteriophage genome. Ligases are enzymes that catalyze
the formation of a phosphodiester bond between the 3'-hydroxyl group of
a segment of donor DNA and the 5'-phosphate group of the vector DNA .
Avector is a DNA molecule into which foreign DNA moleules are ligated
and inserted into cells so that the recombinant DNA can be replicated. Plasmid
vectors must also contain a marker, such as an antibiotic resistance
gene, to facilitate the selection of bacterial cells that contain the plasmid.
Vectors can be introduced into host cells by transformation or transduction. An expression vector is a vector that carries a gene that
can be efficiently transcribed and translated by the host cell.
Characteristics of a good vector:
Variety of single cut sites