Technical brief: A method for analysis of gene expression in isolated mouse photoreceptor and Müller cells

Purpose: Molecular analysis of complex phenomena, such as selective death of photoreceptors and their rescue by neuro-protective agents, has been hindered by limitations of techniques for investigating gene expression in individual cells within a heterogeneous tissue such as the retina. The purpose of this study was to develop methods to assess gene expression in single retinal cells. Methods: Individual cells from papain-dissociated mouse retinae were captured with micropipettes and identified by morphology and by immunocytochemistry. Single cell cDNA libraries were generated by poly-d (T)-primed reverse transcription, poly-d(A) tailing of first strand cDNA, and en masse PCR-amplification using a custom made oligo-d(T). PCR was used to investigate gene expression in cDNAs from individual cells. Results: Dissociated rod and Müller glia cells maintained their morphology, which correlated with their immunocytochemical properties. RPE cells were recognized by their pigmentation. With the exception of bipolar cells, non-photoreceptor neurons were only identifiable by immunocytochemistry. Abundant cDNA could be synthesized from each individual cell. Cell-specific "markers" were detected by PCR almost exclusively in the predicted cell types. The expression of neurotrophic factor receptors was consistent with previous biological studies. Conclusions: These studies establish a method to compare, investigate, and analyze gene expression in individual cells of the retina.