Abstract
Purpose: :
We have previously shown that the expression of Prickle1 (Pk1), a core component of the planar cell polarity (PCP) signaling pathway, is down-regulated in cone-like photoreceptors of the Nrl-knockout retina (Akimoto et al., 2006). To investigate it’s potential role in rod photoreceptor polarity and morphogenesis, we have studied Pk1 expression during retinal development in the mouse. We have also investigated its potential function using shRNA knockdown technology in the postnatal retina.
Methods: :
In situ hybridization (ISH) was used to study the spatial and temporal expression of Pk1 in the retina and the brain. In vivo electroporation was used to introduce shRNA into postnatal retina to knockdown Pk1 expression. Immunohistochemistry (IHC) was performed to study retinal differentiation.
Results: :
Pk1 is expressed in postmitotic neurons of the central nervous system prominently in the hippocampus, striatum, and olfactory cortex. In the retina, Pk1 is expressed in the apical, likely postmitotic, cells in the retina at an early postnatal age. In the adult retina, it is weakly expressed in the inner nuclear and retinal ganglion cell layer (GCL). Knockdown of Pk1 by shRNA led to sustained Ki67 expression and down-regulation of rhodopsin expression.
Conclusions: :
Pk1 has a potential role in coordination of photoreceptor differentiation in early postnatal retina. It might be involved in maintaining a state of differentiation in immature photoreceptor cells.
Keywords: retinal development • signal transduction • genetics