Purchase this article with an account.
Chuan-Chin Chiao, Yin-Peng Chen, Hung-Ya Tu, Yenlin Chen, Ching-Kang Chen; Transgenic Mouse Line Expressing Grik4-cre Targets Multiple Types of Retinal Ganglion Cells. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4582.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Mouse lines expressing Cre recombinase are useful tools for cell-specific genetic manipulation in studying mechanisms of retinal function and diseases. The Grik4-cre (Jax no. 006474) was recently reported to have specific Cre expression in bistratified retinal ganglion cells (RGCs). In light of its potential utility in targeting ON-OFF direction selective ganglion cells, we sought to systematically characterize cells in the ganglion cell layer (GCL) in this Cre driver line.
Cre-mediated recombination was identified in offspring of a male Grik4-cre mated to a female Ai9 reporter (Jax no. 007909). Animals double positive for these two transgenes express tdTomato following Cre-mediated excision of a stop signal. The intrinsic membrane properties of tdTomato positive GCL cells in flat-mount retinas, perfused with mammalian Ringer’s solution and visible by direct fluorescence, were determined by current clamp recordings in the whole-cell configuration with simultaneous biocytin filling. Morphology of recorded cells was revealed by post hoc staining using dye-conjugated streptavidin and subjected to quantitative morphometric analyses and classifications.
We found that cells expressing tdTomato have different soma sizes and that all recorded cells spiked when depolarized above action potential threshold. Both monostratified and bistratified RGCs were found. Furthermore, we found that dendrites of some bistratified RGCs do not costratify with starburst amacrine cells, while others costratify and cofasiculate with them. RGCs with similar morphological features tend to have more than one discernable intrinsic membrane properties to further divide them into additional subgroups.
The Grik4-cre mouse line does not target a single type of RGCs, instead it targets many types with different intrinsic membrane properties and dendritic features. Combining genetic marking and intrinsic membrane property may allow more reliable RGC identification prior to experimentation. The diversity of RGC types in mouse may further be investigated using other Cre driver lines.
This PDF is available to Subscribers Only