Abstract
Purpose: :
PODXL2 (also known as Endoglycan) is a protein closely related to CD34 and podocalyxin. Recent studies have implicated PODXL2 in leukocyte functions, while our own protein association assays have indicated potential interactions with retinal proteins involved in the development of Usher Syndrome. Little is currently known about this protein’s role in healthy retinal function. This study seeks to determine the tissue expression pattern of PODXL2 and eludicate its role in retinal function and maintenance using genetic mouse models.
Methods: :
We developed mutant lines of mice with VelociGene’s predesigned construct (#10133) from the KOMP. Expression of PODXL2 mRNA and protein was evaluated by RT-PCR, Immunoblotting, Immunofluorescence, and by following a lacZ reporter gene embedded in the gene targeting construct. Retinal function in the PODXl2 mice was assessed by ERG recordings.
Results: :
The knockout construct integration has been confirmed in PODXL2 -/- mice, with several regions of the brain and retinal ganglion cells staining positive for the construct’s reporter lacZ sequence. PODXL2 +/- mice breeding has suggested that while -/- mice do survive, they survive less often than PODXL2 +/- or +/+ mice. No disparity in retinal functionality has been detected by noninvasive ERG evaluations done in mice up to two months of age.
Conclusions: :
Further molecular characterization of our -/- mice is needed to evaluate the importance of PODXL2 expression in the mouse retina, to identify splice variations in the PODXL2 gene, and to find if other PODXL2 protein family members are able to compensate for loss of PODXL2 in PODXL2 -/- mice. These results will help elucidate how PODXL2 contributes to retinal function and degeneration and what retinal pathologies it may influence.
Keywords: retina • gene/expression • ganglion cells