Spatiotemporal dynamics of bipolar cell differentiation in the rod-only retina of Leucoraja erinacea
Elvira Magaña
Department of Biology
Faculty Supervisor: Ivan Anastassov
The Little Skate (Leucoraja erinacea) possesses a rod-only, simplex retina, providing a unique system to study retinal development in the absence of cone-driven circuitry. However, little is known about how bipolar cell lineages are specified or how nascent bipolar cells mature in such systems. Here, we examine the spatiotemporal expression of the transcription factor OTX2 and the functional genes PKCα, PKCε, TRPM1, and Neto1l across early, mid, and late developmental stages to characterize bipolar cell differentiation. Multiplex fluorescent in situ hybridization with HCR amplification and confocal imaging was performed on cryosectioned retinas. OTX2 is broadly expressed early and becomes progressively restricted to peripheral growth zones with maturation. PKCα expression precedes TRPM1, suggesting early bipolar cell differentiation, while TRPM1 signal increases over time, consistent with maturation of ON bipolar function. Analyses of PKCε and Neto1l are ongoing and will determine whether these markers distinguish distinct bipolar subtypes or reflect sequential stages of maturation. Together, these findings support a temporal sequence of bipolar cell development in a rod-only retina.