The effects of a CD81 null mutation on retinal pigment epithelium in mice.

The present study examines the effects of Cd81-null mutation on the development of the retinal pigment epithelium (RPE), specifically cell size and number of cells with multiple nuclei. The outlines of RPE in retinal flat mounts were stained with rhodamine-labeled phalloidin and RPE nuclei with Hoechst stain. The RPE layer was sampled to define the number of cells, the size of the RPE cells and the number of nuclei within the cells. The Cd81-null mutation caused an increase in the number of cells within the RPE layer. The cells were smaller than those in the wild type mice. Furthermore there was an increase in the number of mono-nucleated cells. In the posterior portion of the eye there was a significant increase in the number of multi-nucleated cells. The data indicate that CD81 plays a significant role in the final stages of RPE development, controlling cell number and overall developmental pattern.