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A Novel Insertion Variant of CRYGD Is Associated with Congenital Nuclear Cataract in a Chinese Family.

Zhuang X, Wang L, Song Z, Xiao W - PLoS ONE (2015)

Bottom Line: A significantly reduced solubility was observed for this mutant.We have identified a novel mutation, c.451_452insGACT, in CRYGD, which is associated with nuclear cataract.The mutant protein, with loss of solubility and localization to the nucleus, is hypothesized to be the major cause of cataract in these patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Shengjing Hospital, China Medical University, Shenyang, China; Department of Ophthalmology, The Fourth People's Hospital of Shenyang, Shenyang, China.

ABSTRACT

Objective: To investigate a novel insertion variant of CRYGD identified in a Chinese family with nuclear congenital cataract.

Methods: A Chinese family with congenital nuclear cataract was recruited for the mutational screening of candidate genes by direct sequencing. Recombinant N-terminal Myc tagged wildtype or mutant CRYGD was expressed in HEK293T cells. The expression pattern, protein solubility and subcellular distribution were analyzed by western blotting and immunofluorescence.

Principal findings: A novel insertion variant, c.451_452insGACT, in CRYGD was identified in the patients. It causes a frameshift and a premature termination of the polypeptide to become Y151*. A significantly reduced solubility was observed for this mutant. Unlike wildtype CRYGD, which existed mainly in the cytoplasm, Y151* was mis-located in the nucleus.

Conclusions: We have identified a novel mutation, c.451_452insGACT, in CRYGD, which is associated with nuclear cataract. This is the first insertion mutation of CRYGD found to cause autosomal dominant congenital cataract. The mutant protein, with loss of solubility and localization to the nucleus, is hypothesized to be the major cause of cataract in these patients.

No MeSH data available.


Related in: MedlinePlus

Bioinformatics analysis of the mutant CRYGD Y151*.(A) The predicted secondary structure showing the reduced extended strand and random coil in the mutant. (B) The C-terminal domain of the truncated CRYGD favors the unfolded state. The residue-specific stability constant (Kf) for each residue of the protein was predicted by the BEST/COREX server.
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pone.0131471.g003: Bioinformatics analysis of the mutant CRYGD Y151*.(A) The predicted secondary structure showing the reduced extended strand and random coil in the mutant. (B) The C-terminal domain of the truncated CRYGD favors the unfolded state. The residue-specific stability constant (Kf) for each residue of the protein was predicted by the BEST/COREX server.

Mentions: The mutant protein was truncated by 24 amino acids at the C-terminus when compared with the wildtype, and the fourth Greek key motif (amino acid 129–171) was partially absent. Both the extended strand and the random coil were reduced, resulting in destruction of the secondary structure (Fig 3A). The truncated CRYGD had an acidic isoelectric point (PI), which may be involved in protein aggregation. The mutation rendered CRYGD more unstable and decreased its solubility (Table 1). Moreover, the stability constant (Kf) at the per residue level showed that the mutant CRYGD favored the unfolded states at the C-terminus (Fig 3B).


A Novel Insertion Variant of CRYGD Is Associated with Congenital Nuclear Cataract in a Chinese Family.

Zhuang X, Wang L, Song Z, Xiao W - PLoS ONE (2015)

Bioinformatics analysis of the mutant CRYGD Y151*.(A) The predicted secondary structure showing the reduced extended strand and random coil in the mutant. (B) The C-terminal domain of the truncated CRYGD favors the unfolded state. The residue-specific stability constant (Kf) for each residue of the protein was predicted by the BEST/COREX server.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493073&req=5

pone.0131471.g003: Bioinformatics analysis of the mutant CRYGD Y151*.(A) The predicted secondary structure showing the reduced extended strand and random coil in the mutant. (B) The C-terminal domain of the truncated CRYGD favors the unfolded state. The residue-specific stability constant (Kf) for each residue of the protein was predicted by the BEST/COREX server.
Mentions: The mutant protein was truncated by 24 amino acids at the C-terminus when compared with the wildtype, and the fourth Greek key motif (amino acid 129–171) was partially absent. Both the extended strand and the random coil were reduced, resulting in destruction of the secondary structure (Fig 3A). The truncated CRYGD had an acidic isoelectric point (PI), which may be involved in protein aggregation. The mutation rendered CRYGD more unstable and decreased its solubility (Table 1). Moreover, the stability constant (Kf) at the per residue level showed that the mutant CRYGD favored the unfolded states at the C-terminus (Fig 3B).

Bottom Line: A significantly reduced solubility was observed for this mutant.We have identified a novel mutation, c.451_452insGACT, in CRYGD, which is associated with nuclear cataract.The mutant protein, with loss of solubility and localization to the nucleus, is hypothesized to be the major cause of cataract in these patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Shengjing Hospital, China Medical University, Shenyang, China; Department of Ophthalmology, The Fourth People's Hospital of Shenyang, Shenyang, China.

ABSTRACT

Objective: To investigate a novel insertion variant of CRYGD identified in a Chinese family with nuclear congenital cataract.

Methods: A Chinese family with congenital nuclear cataract was recruited for the mutational screening of candidate genes by direct sequencing. Recombinant N-terminal Myc tagged wildtype or mutant CRYGD was expressed in HEK293T cells. The expression pattern, protein solubility and subcellular distribution were analyzed by western blotting and immunofluorescence.

Principal findings: A novel insertion variant, c.451_452insGACT, in CRYGD was identified in the patients. It causes a frameshift and a premature termination of the polypeptide to become Y151*. A significantly reduced solubility was observed for this mutant. Unlike wildtype CRYGD, which existed mainly in the cytoplasm, Y151* was mis-located in the nucleus.

Conclusions: We have identified a novel mutation, c.451_452insGACT, in CRYGD, which is associated with nuclear cataract. This is the first insertion mutation of CRYGD found to cause autosomal dominant congenital cataract. The mutant protein, with loss of solubility and localization to the nucleus, is hypothesized to be the major cause of cataract in these patients.

No MeSH data available.


Related in: MedlinePlus