Cos site
The sequence that is cut to produce the cohesive, single-stranded extensions located at the ends of the linear DNA molecules of certain phages (e.g. lambda).
Cosanguine
Related by a common ancestor.
The DNA passes through a separate sugar transport protein (ptsG) in the inner membrane, and immediately circularises using the cos sites, 12-base G-C rich cohesive "sticky ends". The single-stranded nicks are ligated by host DNA ligase.
These are plasmids carrying a phage l cos site (which allows packaging into l capsids), an origin of replication and an antibiotic resistance gene. A plasmid of 40 kb is very difficult to put into bacteria, but can replicate once there.
lambda Any type of cloning vector (cosmids) containing cos sites necessary for propagation in bacteriophage lambda. Cosmid clones can be used to clone DNA fragments of up to 15 kb.
library A collection of clones in any type of vector.
development of a new large-fragment cloning vector, the bacterial artificial chromosome (BAC), which is based on an F factor modified to contain a COS site, a selectable marker, polymerase initiation sites, and cloning sites.
 See also: Chromosome, Cloning, Cell, Trans, Bacteria
|
