Studies of congenital cataract-related TSR1 mutation and its expression in the lens

Congenital cataract (CC) is a rare disease with dysplasia of the lens, mainly characterized by partial or complete opacity of the lens. The molecular basis of the disease is complex, mutations in over 266 genes associated with congenital cataracts had been reported. In this study, a novel congenital cataract candidate gene TSR1 was identified by whole genome sequencing and Sanger sequencing in a Chinese congenital cataract family. The TSR1 c.202-1G>A substitution affected splicing of TSR1 mRNA was confirmed by a minigene assay. The expression of TSR1 in mouse lens, anterior lens capsule of age-related cataract patients and 24-week human fetal lens were determined by RT-PCR, Western blotting, and immunofluorescence assays. The expression of TSR1 in the embryonic and different developmental stages of the mouse lens was confirmed by analyzing the iSyTE database. The expression of TSR1 was down-regulated in the lens-specific CBP:p300 double knockout mouse, and a set of genes with the same expression pattern of Tsr1 in the CBP:p300 double knockout mouse lens were extracted for protein-protein interaction network analysis, and six proteins were screened for direct interaction with Tsr1. GO function analysis indicated that Tsr1 might play a role in the MAPK-Erk signaling pathway in addition to its involvement in ribosome assembly. This study provided valuable research clues to further clarify the function of Tsr1 in the lens.