A novel zebrafish gene expressed specifically in the photoreceptor cells of the retina

We have identified and characterized a novel protein from adult zebrafish retina, which we named ES1, Database search revealed that the ES1 gene has significant similarity to two genes with unknown functions: the Escherichia coli sigma cross-reacting protein 27a (scrp27a) and the human KNP-I/GT335. In situ hybridization and immunohistochemistry experiments showed that both ES1 mRNA and protein are expressed specifically in adult photoreceptor cells, ES1 seems to be a cytoplasmic protein, An ES1-like antigen was also detected in photoreceptor cells of goldfish with anti-ES1 antibodies. The retina specific expression and the evolutionary conservation suggest that ES1 protein may be important for maintaining normal retina structure and function. (C) 1997 Academic Press.