DISCRETE STAGES OF ANTERIOR-PITUITARY DIFFERENTIATION RECAPITULATED IN IMMORTALIZED CELL-LINES

Targeted expression of oncogenes in transgenic mice can immortalize sp ecific cell types to serve as valuable cultured model systems. Utilizi ng promoter regions from pituitary genes activated in the gonadotrope/ thyrotrope lineage at discrete stages of development, we have demonstr ated that targeted oncogene expression in transgenic mice can produce cell lines representing sequential stages of differentiation. Each cel l line expresses a specific subset of the genes denoting differentiate d function such as the subunits of the glycoprotein hormones, hormone receptors, and transcriptional regulatory proteins. These model system s have allowed detailed investigations into molecular and cellular mec hanisms otherwise inaccessible in vivo or in complex primary pituitary cell cultures. (C) 1998 Elsevier Science Ireland Ltd. All rights rese rved.