FUNCTIONAL CHARACTERIZATION OF RNA BINDING PROTEIN CAPRIN2 IN MOUSE EYE DEVELOPMENT
Date
2017-05
Authors
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Publisher
University of Delaware
Abstract
The iSyTE bioinformatics tool developed by the Lachke laboratory previously
identified that a novel RNA binding protein (RBP) and RNA granule component,
Caprin2, is enriched in the mouse lens at the early embryonic (E) day 10.5 and later
stages. It was demonstrated that Caprin2 mRNA and protein were localized to lens
fiber cells, supporting the hypothesis that it has potential function in lens development.
It was also demonstrated that a lens-specific conditional mouse knockout of Caprin2
(Caprin2cKO/cKO) resulted in nuclear fiber cell compaction and a persistent lenti-corneal
stalk. However, the lenti-corneal stalk phenotype was only observed at 8% penetrance
in Caprin2cKO/cKO mouse eyes. We hypothesized that one of the reasons for the low
penetrance of this ocular defect may result from residual Caprin2 protein present at
E12.5 in the mutant mice. Therefore, Caprin2 germline (Caprin2-/-) deletion knockout
mouse mutants that would lack Caprin2 protein earlier in embryogenesis were
generated to test this hypothesis. Phenotypic characterization involving histology and
scanning electron microscopy did not reveal any obvious ocular defects in Caprin2-/-
mice. Further analyses revealed that Caprin1, a paralogous RNA binding protein, is
upregulated in the Caprin2-/- lens. Interestingly, while Caprin1 protein levels were
elevated, its mRNA was not found to be significantly different in Caprin2-/- lenses at
E14.5, suggesting a potential post-transcriptional mechanism as the basis of the
Caprin1 up-regulation in the mutant lens. These findings suggest that removal of
Caprin2 earlier in embryogenesis causes the up-regulation of Caprin1 that may result
in redundancy and “rescue” of the ocular defects observed in Caprin2cKO/cKO mouse
eyes. Therefore, Caprin1 and Caprin2 double knockout mouse mutants may need to
be generated to test this hypothesis in the future.
Description
Keywords
Biology, Biologicial Sciences, RNA BINDING PROTEIN CAPRIN2, MOUSE EYE DEVELOPMENT