A novel CRYGD mutation (p.Trp43Arg) causing autosomal dominant congenital cataract in a Chinese family

Abstract

To identify the genetic defect associated with autosomal dominant congenital nuclear cataract in a Chinese family, molecular genetic investigation via haplotype analysis and direct sequencing were performed Sequencing of the CRYGD gene revealed a c.127T>C transition, which resulted in a substitution of a highly conserved tryptophan with arginine at codon 43 (p.Trp43Arg). This mutation co-segregated with all affected individuals and was not observed in either unaffected family members or in 200 normal unrelated individuals. Biophysical studies indicated that the p.Trp43Arg mutation resulted in significant tertiary structural changes. The mutant protein was much less stable than the wild-type protein, and was more prone to aggregate when subjected to environmental stresses such as heat and UV irradiation. © 2010 Wiley-Liss, Inc.

The Human W42R γD-Crystallin Mutant Structure Provides a Link between Congenital and Age-related Cataracts*

“…Our finding is therefore different from a previous report that found no noticeable difference between HGD and W42R solubility (26). Note that both protein constructs that were used in the previous study contained His tags and that the analysis was carried out at low protein concentration (5 mg/ml) at a single temperature (26 Fig. 1A, the mutant exhibits equally well dispersed resonances of uniform line widths as the wild-type protein, with most resonances overlapping or shifted only by a small amount.…”

“…Indeed, the wild-type protein can be concentrated to ϳ350 mg/ml, whereas the mutant protein readily precipitates when the protein concentration reaches ϳ20 mg/ml. Our finding is therefore different from a previous report that found no noticeable difference between HGD and W42R solubility (26). Note that both protein constructs that were used in the previous study contained His tags and that the analysis was carried out at low protein concentration (5 mg/ml) at a single temperature (26 Fig.…”

“…Recently, a novel mutation in HGD was discovered in a Chinese family, with the affected individuals exhibiting nuclear congenital cataracts (26). A single T/C change at position 127 in the CRYGD gene was mapped, translating into a tryptophan to arginine change at position 42 (W42R) in the amino acid sequence of the mature protein, i.e.…”

“…the loss of one of the four conserved tryptophans from the protein. The W42R mutant protein was reported to be less stable and more prone to aggregate when subjected to environmental stresses, such as heat and UV irradiation, when compared with HGD (26). However, no structural or other biochemical characterizations were carried out to elucidate how this mutation could lead to cataract formation.…”

A novel mutation impairing the tertiary structure and stability of γC-crystallin (CRYGC) leads to cataract formation in humans and zebrafish lens

“…• C. The UV-resistance of the proteins was performed according to the procedure published elsewhere [Wang et al, 2011]. The samples were placed on ice to avoid heating by the UV light, exposed to UV irradiation (30 W, 254 nm), and the turbidity of the samples was measured every 2 hr on an Ultraspec 4300 pro UV/Visible spectrophotometer.…”