Cataract- and lens-specific upregulation of ARK receptor tyrosine kinase in emory mouse cataract

PURPOSE. The Emory mouse is a well-characterized model for age-onset cataract. The purpose of the present study was to identify differentially expressed genes between pre- and postcataract Emory mouse lenses. METHODS. Eyes were extracted from Emory mice at 3 weeks (precataract) and 7.5 months (postcataract) of age, and lenses were dissected. Lens RNA was compared for gene expression differences by RT-PCR differential display, and transcripts exhibiting altered levels of gene expression were cloned and identified by sequencing. The levels of two transcripts were further evaluated by RT-PCR in 3-week- and 7.5-month-old lenses and the remainder of the eye. The same transcripts were also measured in lenses from three non-Emory mouse strains (FVB/N, 129Sv, and CD1) ages 4 weeks to 11.5 months. RESULTS. Three transcripts were identified as exhibiting altered levels of gene expression between 3-week- and 7,5-month-old Emory mouse lenses. These encoded αA-crystallin (decreased), βA3/A1-crystallin (decreased), and adhesion-related kinase (ARK) receptor tyrosine kinase (increased). Decreased aA-crystallin and increased ARK expression were not detected in lenses isolated from three non-Emory mouse strains of similar age. Increased expression of ARK was not detected between 3-week- and 7.5-month-old Emory mouse eye nonlens tissues. CONCLUSIONS. The present data confirm that expression of the αA-crystallin gene is decreased in cataract in the Emory mouse lens relative to age-matched control lenses and they provide evidence for cataract- and lens-specific upregulation of the ARK receptor tyrosine kinase in the Emory mouse.