Functional Characterization of Caprin2 in Mouse Eye Development and Its Associated Developmental Defect Peters Anomaly

Abstract

Using the iSyTE bioinformatics tool developed by our lab we identified a novel RNA binding protein and RNA granule component Caprin2 that is enriched at early mouse embryonic time points starting at embryonic time point (E) 10.5 onward based on microarray data. In situhybridization (ISH) and immunostaining experiments were performed on mouse embryonic lens tissue to validate these findings. This analysis demonstrated that Caprin2 mRNA and protein were localized to lens fiber cells, supporting the hypothesis that it has potential function in lens development. Recently, our lab demonstrated that a lens‐specific conditional knockout of Caprin2 (Caprin2cko/cko) caused compaction of the central region of lens fiber cells and Peters anomaly, a lenti‐corneal stalk. However, the Peters anomaly defect showed only 8% penetrance in Caprin2cko/cko mice. We hypothesized the low penetrance of this ocular defect resulted from the residual Caprin2 protein present at E12.5 in the mutant mice. Caprin2 germline (Caprin2‐−/−) deletion knockout mouse mutants were generated to test this hypothesis. Caprin2 protein was confirmed to be deleted constitutively through western blotting and immunostaining on Caprin2‐−/− lenses at birth and at E14.5 respectively. Phenotypic characterization has thus far been performed on the Caprin2‐−/− mice through embryonic histology and scanning electron microscopy. Histology of the mouse mutant demonstrated no significant morphological difference from wild type mice. Scanning electron microscopy also had no significant difference, though more samples remain to be analyzed. Further analyses will include immunostaining for important lens development markers including Pax6, Foxe3, p63, Spry1/2, and Shrm3.