Dexamethasone inducible gene expression optimised by glucocorticoid antagonists

摘要

Inducible expression of a specific target gene is a powerful tool to analyse factors involved in growth stimulation, cell cycle progression, oncogenic transformation or apoptosis. In an ideal system, the transfected gene should be a priori tightly repressed and strong induction should occur within a short time after stimulation. Conditional expression vectors based on endogenous mammalian control sequences from the metallothioneine gene promoter (1), heat shock factor promoter (2) and glucocorticoidresponsive elements (3,4) have been reported (for review see 5). Drawbacks of these systems include leakiness at the inactive state and interference from other gene products by the induction conditions. Recently developed estrogen receptor-GAL4 fusion constructs exhibit high inducibility without side effects only in transient expression (6) but not in stably transfected cells (W. Mikulits, unpublished).