Abstract
Purpose: :
To characterize a restricted subset of GFP positive amacrine cells in a transgenic mouse line by using immunocytochemistry, electrophysiology and gene expression analysis.
Methods: :
We characterized a novel transgenic mouse line in which a restricted subset of amacrine cells is labeled with green fluorescent protein (GFP). Immunohistochemical markers were used to classify the GFP labeled cell. Light responses were measured using electrophysiological methods. After fluorescence activated cell sorting (FACS) of approximately 200 cells and RNA amplification, gene expression pattern was determined using Affymetrix mouse gene arrays.
Results: :
Morphological analysis revealed that the GFP labeled cell in our transgenic mouse line is the A17 amacrine cell. The cells terminate in the same stratum as the rod bipolar cells and make contacts with rod bipolar cells. The A17 amacrine cells are negative for the AII marker Dab1, and for the neurotransmitter glycine but positive for GABA and GAD65/67. The combination of 2-photon imaging and electrophysiological recordings revealed that the cell is an ON cell and is able to respond under scotopic conditions. The gene expression data showed a significant upregulation of several gene classes, for example of genes responsible for GABA production, compared to expression data from another genetically identified amacrine cell.
Conclusions: :
We identified a transgenic mouse line in which a subtype of amacrine cell is labeled. Immunohistochemical analysis, electrophysiology and the gene expression data suggest that this cell type is the A17 amacrine cell. This work opens the door for analyzing the function and development of an as yet not well characterized cell type in the rod pathway.
Keywords: amacrine cells • gene microarray • gene/expression