Mice hemizygous for this GAD67-GFP transgene are viable and fertile. In the hippocampus, GAD67-GFP (line 3) mice selectively express enhanced green fluorescent protein (EGFP) in newborn dentate granule cells. At two weeks of age, EGFP is expressed in large numbers of dentate granule cells, and the number of EGFP-positive cells diminishes with age in a pattern consistent with the postnatal development of dentate granule cells/age-related reduction in adult neurogenesis in the dentate gyrus. The EGFP expression in newborn dentate granule cells begins within the first week of cell division and disappears as newborn neurons mature (about 4 weeks postmitotic), and EGFP positive dentate granule cells also express the newborn neuron markers PSA-NCAM and doublecortin. The bright labeling of newborn neurons with EGFP makes it possible to visualize the details of dendrites, which reach the outer edge of the molecular layer, and
their axon terminals (mossy fiber boutons) in the CA3 region. In addition, EGFP is expressed in GABAergic neurons in many regions of the brain including the Purkinje cells of the cerebellum, periglomerular neurons of the olfactory
bulb, and interneurons of the superior colliculus and brainstem. In some regions of the brain (thalamus, hypothalamus, cortex and striatum) sparse EGFP labeling is seen, with all EGFP positive cells also GAD67 positive in these regions. EGFP expression is not reported in hippocampal interneurons, including those in the hilus. Because the transgene contains loxP sites surrounding the GAD67-GFP sequences, crossing to a cre expressing strain will result in offspring bearing a deletion of the GAD67-GFP transgene. These GAD67-GFP (line 3) mice may be useful for fluorescent labeling of neurons and studying the development, maturation, regulation, and functional integration of newborn neurons in adult hippocampus.

Of note, this GAD67-GFP strain is one of many fluorescent GABAergic neuron strains, each with unique labeling characteristics (see Stock No. 003718, Stock No. 006334, Stock No. 006340, and Stock No. 007677).