We have cloned and characterized the chicken GS gene and are presently identifying genetic elements important for its expression in retinal M ller glial cells. Our research has established that retinal primary cultures and, more surprisingly, intact retinal organ cultures are amenable to the expeditious methods of gene transfer and analysis routinely used to characterize genetic control elements in continuous cell lines. Current efforts are focused on relating the functioning of various control elements to the regulation of GS gene expression during retinal development, and to identify protein transcription factors that guide this process. With an eye toward future pharmacologic intervention, our laboratory is attempting to elucidate the physiologically relevant modes of transcriptional control of the human NOS1 gene. Moreover, a novel genetic structure, involving closely linked but separable promoters, is responsible for this effect.
Protein kinase A activation of glucocorticoid-mediated signalling in the embryonic retina.
Two closely linked but separable promoters for human neuronal nitric oxide synthase gene transcription. A transcriptional enhancer of the glutamine synthetase gene that is selective for retinal M ller glial cells. Differential regulation of the two neuronal nitric oxide synthase gene promoters by the Oct-2 transcription factor. Steroid hormone receptors activate transcription in glial cells of intact retina but not in primary cultures of retinal glial cells.