The Department of Biological Sciences at the University of Notre Dame is pleased to present a seminar by Ann Morris, assistant professor of biology at the University of Kentucky.
The overall goal of the Morris laboratory's research is to understand the genetic pathways that regulate ocular development, cellular differentiation, and photoreceptor regeneration in the neural retina of the zebrafish. Previously, they identified the transcription factor Sox11 as a candidate regulator of rod photoreceptor regeneration in zebrafish. Sox11 is a member of the SoxC family of HMG-box containing transcriptional regulators. Sox11 is known to regulate neurogenesis in the brain and spinal cord, and is also required for the proper development of several organ systems. Using a combination of morpholino-mediated gene knockdown and pharmacologic manipulation, they found that Sox11-deficient zebrafish exhibit ocular abnormalities such as microphthalmia, delayed and abnormal lens development, coloboma (a persistently open choroid fissure), and a specific deficit in rod photoreceptor differentiation, all of which could be rescued by blocking Hh signaling (or exacerbated by augmenting Hh signaling). Moreover, they found that Sox11 negatively regulates levels of Hedgehog signaling by repressing transcription of the gene for the Sonic Hedgehog a ligand (shha). They also provide evidence that mutations or altered gene dosage of SOX11 contribute to microphthalmia, coloboma, and rod photoreceptor dysfunction in human patients. We propose that Sox11 regulates ocular morphogenesis and photoreceptor development through its control of Shh signaling.
The results of Morris' research will provide a better understanding of the genetic basis for ocular morphogenesis and photoreceptor development. In integrating model organism research with human genetics, our studies have the potential to make a direct contribution to the identification and management of ocular birth defects.
Originally published at biology.nd.edu.