Regulable Expression of Inhibin A in Wild-Type and Inhibinα Null Mice

Exogenous regulation of protein expression creates the potential to examine the consequences of homeostatic Dysregulation in many physiological systems and, when used in transgenic mice, provides the capability of restoring a gene product to its knockout background without antigenicity issues. In this study, we used a mifeprisone-inducible system (the GeneSwitch system) to regulate the expression of inhibin A from the liver of mice. Inhibin is a heterodimeric protein (α/β) wherein one of its subunits (β) is capable of homodimerizing to form its physiological antagonist, activin (β/β). Inhibin is also expressed in two forms, A and B, as determined by the subtype of β-subunit that dimerizes with theα -subunit (α/βA or α/βB). To utilize the GeneSwitch system, transgenic transactivator mice with liver-specific expression of a mifepristone-activated chimeric nuclear receptor (GLVP) were crossed with transgenic target mice containing a GVLP-responsive promoter upstream of poliovirus IRES (internal ribosome entr...