A shuttle vector is a vector constructed so that it can propagate in two different host species. Therefore, DNA inserted into a shuttle vector can be tested or manipulated in two different cell types.
It has two origins of replication, each of which is specific to a host. Since shuttle vectors replicate in two different hosts, they are often known as bifunctional vectors.
One of the most common types of shuttle vectors is the yeast shuttle vector. Almost all commonly used Saccharomyces cerevisiae vectors are shuttle vectors. Yeast shuttle vectors have components that allow for replication and selection in both E.coli and yeast cells. The E.coli component of a yeast shuttle vector includes an origin of replication and a selectable marker, e.g., antibiotic resistance, beta lactamase. The yeast component of a yeast shuttle vector includes autonomously replicating sequence (ARS), a yeast centromere (CEN) and a yeast selectable marker (e.g., URA3, a gene that encodes an enzyme for uracil synthesis).
Example of Shuttle Vector: pHV14, pEB10, pHP3, etc. replicate both in Bacillus subtilis and E.coli.
pJDB219 is another shuttle vector that can replicate in E.coli and Yeast. pJDB219 is another shuttle vector that can replicate in E.coli and Yeast (Saccharomyces cerevisiae ).
An expression vector is generally a plasmid that is used to introduce a specific gene into a target cell. Once the expression vector is inside the cell, the protein that is encoded by the gene is produced by the cellular transpiration and translation machinery ribosomal complexes. The plasmid is frequently engineered to contain regulatory sequences that act as enhancer and promoter regions and lead to efficient transcription of the gene carried on the expression vector.