An Efficient and Versatile System for Visualization and Genetic Modification of Dopaminergic Neurons in Transgenic Mice.

Helia Aboutalebi,Edgar R Kramer,Xiaoxi Zhuang,Karsten Tillack

doi:10.1371/journal.pone.0136203

Helia Aboutalebi, Edgar R Kramer + Show 2 more

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https://doi.org/10.1371/journal.pone.0136203

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Abstract

Background & AimsThe brain dopaminergic (DA) system is involved in fine tuning many behaviors and several human diseases are associated with pathological alterations of the DA system such as Parkinson’s disease (PD) and drug addiction. Because of its complex network integration, detailed analyses of physiological and pathophysiological conditions are only possible in a whole organism with a sophisticated tool box for visualization and functional modification.Methods & ResultsHere, we have generated transgenic mice expressing the tetracycline-regulated transactivator (tTA) or the reverse tetracycline-regulated transactivator (rtTA) under control of the tyrosine hydroxylase (TH) promoter, TH-tTA (tet-OFF) and TH-rtTA (tet-ON) mice, to visualize and genetically modify DA neurons. We show their tight regulation and efficient use to overexpress proteins under the control of tet-responsive elements or to delete genes of interest with tet-responsive Cre. In combination with mice encoding tet-responsive luciferase, we visualized the DA system in living mice progressively over time.ConclusionThese experiments establish TH-tTA and TH-rtTA mice as a powerful tool to generate and monitor mouse models for DA system diseases.

Highlights

The DA system in the brain is essential for mental and physical health as it controls many basic processes including movement, memory, motivation and emotion
The brain dopaminergic (DA) system is involved in fine tuning many behaviors and several human diseases are associated with pathological alterations of the DA system such as Parkinson’s disease (PD) and drug addiction
In the last decade several Cre expressing mice have been generated to delete genes of interest in DA neurons using promoters of different genes. They include genes such as tyrosine hydroxylase (TH) [2,3,4], the first and rate-limiting enzyme for dopamine synthesis and highly expressed in DA neurons from early embryonic day 9–10 onwards throughout life [5], dopamine transporter (DAT) [6,7,8,9,10], required for dopamine re-uptake into DA neurons and expressed from embryonic day 9, and Pitx3 [11], a transcription factor involved in DA neurons differentiation

Summary

Introduction

The DA system in the brain is essential for mental and physical health as it controls many basic processes including movement, memory, motivation and emotion. In the last decade several Cre expressing mice have been generated to delete genes of interest in DA neurons using promoters of different genes. Even mice with estrogen-regulated Cre under the control of the DAT [12], Pitx-3 [13], or TH promoter [14] were generated for temporarily controlled gene deletions. In these mice, Cre recombinase is fused to a truncated estrogen receptor (CreER) and Cre activation can be regulated with the estrogen receptor antagonist, tamoxifen, which enables translocation of CreER into the nucleus where it can trigger recombination [15]. Because of its complex network integration, detailed analyses of physiological and pathophysiological conditions are only possible in a whole organism with a sophisticated tool box for visualization and functional modification

Methods

Results

Conclusion