Definition: Gene expression vectors

Explanation: Many proteins are expressed at low levels in vivo. To produce high levels of a protein, it is often useful to clone the gene downstream of a well-characterized, regulated promoter. Inducing transcription from the regulated promoter thus results in elevated expression of the downstream gene product. If the regulated promoter can be turned off tightly, this also provides a method of conditionally depleting the cell of a gene product. A variety of regulated promoters can be used for this purpose.