Fluorescent Labeling of Newborn Dentate Granule Cells in GAD67-GFP Transgenic Mice: A Genetic Tool for the Study of Adult Neurogenesis

Shengli Zhao,Li Qiu,Qian Chen,Jimmy Gross,Guoping Feng,Yang Zhou,Dongqing Wang,Pei Miao,Alain Chédotal

doi:10.1371/journal.pone.0012506

Abstract

Neurogenesis in the adult hippocampus is an important form of structural plasticity in the brain. Here we report a line of BAC transgenic mice (GAD67-GFP mice) that selectively and transitorily express GFP in newborn dentate granule cells of the adult hippocampus. These GFP+ cells show a high degree of colocalization with BrdU-labeled nuclei one week after BrdU injection and express the newborn neuron marker doublecortin and PSA-NCAM. Compared to mature dentate granule cells, these newborn neurons show immature morphological features: dendritic beading, fewer dendritic branches and spines. These GFP+ newborn neurons also show immature electrophysiological properties: higher input resistance, more depolarized resting membrane potentials, small and non-typical action potentials. The bright labeling of newborn neurons with GFP makes it possible to visualize the details of dendrites, which reach the outer edge of the molecular layer, and their axon (mossy fiber) terminals, which project to the CA3 region where they form synaptic boutons. GFP expression covers the whole developmental stage of newborn neurons, beginning within the first week of cell division and disappearing as newborn neurons mature, about 4 weeks postmitotic. Thus, the GAD67-GFP transgenic mice provide a useful genetic tool for studying the development and regulation of newborn dentate granule cells.

Highlights

In the dentate gyrus of the hippocampus, new neurons are continually generated and incorporated into the circuitry throughout the lives of all mammals, including humans [1,2,3,4,5,6,7,8,9,10,11]
The GAD67-GFP transgene labels the subgranular zone of dentate gyrus
In order to assist the study of the structure and function of GABAergic neurons, we generated BAC transgenic mice expressing EGFP under the control of GAD67 regulatory elements

Summary

Introduction

In the dentate gyrus of the hippocampus, new neurons are continually generated and incorporated into the circuitry throughout the lives of all mammals, including humans [1,2,3,4,5,6,7,8,9,10,11]. Transgenic mice expressing GFP in newborn dentate granule cells under the control of the proopiomelanocortin (POMC) or the doublecortin (DCX) promoter have been characterized [26,27,28,29]. These mice have greatly facilitated the study of the development and regulation of adult neurogenesis in the dentate gyrus [30,31,32,33]

Methods

Results

Conclusion