Purpose: In humans, the fovea is the region of the retina responsible for acute vision. Disorders affecting the fovea are responsible for the majority of cases of untreated blindness in the developed world, yet are poorly understood at the molecular level. Our goal is to identify genes that are preferentially expressed within the human fovea as compared to the midperipheral retina (differential fovea clones).
Materials and methods: An unamplified fovea cDNA library was differentially screened with cDNA probes derived from either human fovea or midperipheral retina. Rounds of secondary screening and northern analysis were used to verify the expression pattern of a selective number of clones isolated.
Results: Forty-one differential fovea clones were isolated from a screening of 10,000 phage clones (clones). Of these clones, 31.5 % correspond to known sequences present in GenBank/EMBL and 70.7% represent novel human fovea expressed sequence tags (ESTs). Northern analysis of selected clones demonstrated that they represent genes expressed at higher levels in the human fovea than in the midperipheral retina.
Conclusions: Genes that are more highly expressed in the fovea as opposed to the midperipheral retina are likely to represent essential genes for fovea function. Using our fovea cDNA library, we are able to isolate differential human fovea clones at an incidence of 41/10,000 clones screened. We demonstrate that there is a high level of differential gene expression within different regions of the human retina.