Unique and Cell-Type-Specific Tyrosine Hydroxylase Gene Expression

Abstract

Publisher Summary AP1 is an important element for TH gene regulation. Cis-acting elements for tissuekell-type-specific TH gene expression are identified to be localized within a 9.1-kb upstream sequence. Some data suggest that the TH gene is not regulated in a uniform fashion in every cell type, but is regulated in a cell-type-specific manner. This chapter demonstrates data that show unique and cell- type-specific TH gene regulation. Cotransfection of PC12 cells with TH2400CAT plasmid and the expression vector pCMV-ICER-Ib demonstrated that ICER efficiently represses transcriptional activity of the TH gene promoter. In addition, protein kinase A (PKA)-stimulated transcriptional activity of the promoter was effectively suppressed by ICER. These results suggest that ICER can modulate cAMP-stimulated transcription of the TH gene and provide a model accounting for rapid reversal of increased TH transcription following elevations in cAMP. It was demonstrated in the past that TH expression appears permanently within cells destined to be CA-secreting during adult life, and transiently in several cell types that will not express TH in adulthood. The first β-gal expression in the embryonic brain appeared within distinct regions, such as the ventral prosencephalon, the ventral and dorsolateral mesencephalon, and the rostra1 and caudal rhombencephalon. The 9.1 kb upstream region is not sufficient to express in all CA cells in the peripheral nervous system. More studies are necessary to identify proper DNA segment(s) to express in all CA cell types in rat tissues.