Summer Research Description: Retinal diseases, such as retinitis pigmentosa, are extremely common and can lead to partial or total blindness. Unlike mammals, Zebrafish have the ability to completely regenerate their retina, regaining full function after damage. Since the Zebrafish retina closely resembles the human retina, it provides an excellent model to study regeneration and a platform for new target therapies. Zebrafish retina regeneration starts with Müller Glia (MG) proliferation; however, the signals which prompt MG proliferation is unclear. GABAergic Horizontal cells (HC) are directly affected by photoreceptor (PR) death. We propose one initial response following PR death is a decrease in GABA released by HC, which is sensed by the MG. Initial tests show a significant decrease in GABA after PR damage. Another early signaling molecule in retina regeneration is a small non-coding RNA: microRNA 216a. We have shown that the down-regulation of miR-216a is necessary for regeneration. In further testing the downstream signaling pathways of miR-216a, we hope to find the mechanism to which the retina is directly responding and thus elucidate multiple signals that are essential for regeneration.