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Identification of a novel GJA8 (Cx50) point mutation causes human dominant congenital cataracts.

Ge XL, Zhang Y, Wu Y, Lv J, Zhang W, Jin ZB, Qu J, Gu F - Sci Rep (2014)

Bottom Line: Sequencing the coding regions of GJA8, coding for connexin 50, revealed a C > A transversion at nucleotide 264, which caused p.P88T mutation.To dissect the molecular consequences of this mutation, plasmids carrying wild-type and mutant mouse ORFs of Gja8 were generated and ectopically expressed in HEK293 cells and human lens epithelial cells, respectively.The results demonstrate that the molecular consequences of the p.P88T mutation in GJA8 include changes in connexin 50 protein localization patterns, accumulation of mutant protein, and increased cell growth.

View Article: PubMed Central - PubMed

Affiliation: School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang 325027 China.

ABSTRACT
Hereditary cataracts are clinically and genetically heterogeneous lens diseases that cause a significant proportion of visual impairment and blindness in children. Human cataracts have been linked with mutations in two genes, GJA3 and GJA8, respectively. To identify the causative mutation in a family with hereditary cataracts, family members were screened for mutations by PCR for both genes. Sequencing the coding regions of GJA8, coding for connexin 50, revealed a C > A transversion at nucleotide 264, which caused p.P88T mutation. To dissect the molecular consequences of this mutation, plasmids carrying wild-type and mutant mouse ORFs of Gja8 were generated and ectopically expressed in HEK293 cells and human lens epithelial cells, respectively. The recombinant proteins were assessed by confocal microscopy and Western blotting. The results demonstrate that the molecular consequences of the p.P88T mutation in GJA8 include changes in connexin 50 protein localization patterns, accumulation of mutant protein, and increased cell growth.

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Related in: MedlinePlus

Cataracts pedigree and phenotype.(A). Cataracts pedigree. Squares and circles symbolize males and females, respectively. Black and white lines denote affected status and unaffected status, respectively. Arrow indicates proband. Individuals underlined in blue represent those enrolled in the study. + represents wild-type GJA8 allele, − represents allele with mutation. (B). Photographs of affected individuals of this family. The phenotype of the proband (IV: 3) is bilateral complete opacification of the fetal nucleus and the cortex; its phenotype is total cataract.
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f1: Cataracts pedigree and phenotype.(A). Cataracts pedigree. Squares and circles symbolize males and females, respectively. Black and white lines denote affected status and unaffected status, respectively. Arrow indicates proband. Individuals underlined in blue represent those enrolled in the study. + represents wild-type GJA8 allele, − represents allele with mutation. (B). Photographs of affected individuals of this family. The phenotype of the proband (IV: 3) is bilateral complete opacification of the fetal nucleus and the cortex; its phenotype is total cataract.

Mentions: The family comprised 4 affected individuals from a four generation pedigree(Figure 1A).The proband is a 17-year-old male (IV: 3). His phenotype is bilateral complete opacification of the fetal, infantile, and adult nucleus and the cortex, and its phenotype is of total cataracts (Figure 1B), with low vision (20/200). Other family members have similar cataracts patterns. There was no family history of other ocular or systemic abnormalities. Hospital records indicated that the opacity either was present at birth or developed during the first few months of life usually, but did not progress with age.


Identification of a novel GJA8 (Cx50) point mutation causes human dominant congenital cataracts.

Ge XL, Zhang Y, Wu Y, Lv J, Zhang W, Jin ZB, Qu J, Gu F - Sci Rep (2014)

Cataracts pedigree and phenotype.(A). Cataracts pedigree. Squares and circles symbolize males and females, respectively. Black and white lines denote affected status and unaffected status, respectively. Arrow indicates proband. Individuals underlined in blue represent those enrolled in the study. + represents wild-type GJA8 allele, − represents allele with mutation. (B). Photographs of affected individuals of this family. The phenotype of the proband (IV: 3) is bilateral complete opacification of the fetal nucleus and the cortex; its phenotype is total cataract.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927206&req=5

f1: Cataracts pedigree and phenotype.(A). Cataracts pedigree. Squares and circles symbolize males and females, respectively. Black and white lines denote affected status and unaffected status, respectively. Arrow indicates proband. Individuals underlined in blue represent those enrolled in the study. + represents wild-type GJA8 allele, − represents allele with mutation. (B). Photographs of affected individuals of this family. The phenotype of the proband (IV: 3) is bilateral complete opacification of the fetal nucleus and the cortex; its phenotype is total cataract.
Mentions: The family comprised 4 affected individuals from a four generation pedigree(Figure 1A).The proband is a 17-year-old male (IV: 3). His phenotype is bilateral complete opacification of the fetal, infantile, and adult nucleus and the cortex, and its phenotype is of total cataracts (Figure 1B), with low vision (20/200). Other family members have similar cataracts patterns. There was no family history of other ocular or systemic abnormalities. Hospital records indicated that the opacity either was present at birth or developed during the first few months of life usually, but did not progress with age.

Bottom Line: Sequencing the coding regions of GJA8, coding for connexin 50, revealed a C > A transversion at nucleotide 264, which caused p.P88T mutation.To dissect the molecular consequences of this mutation, plasmids carrying wild-type and mutant mouse ORFs of Gja8 were generated and ectopically expressed in HEK293 cells and human lens epithelial cells, respectively.The results demonstrate that the molecular consequences of the p.P88T mutation in GJA8 include changes in connexin 50 protein localization patterns, accumulation of mutant protein, and increased cell growth.

View Article: PubMed Central - PubMed

Affiliation: School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang 325027 China.

ABSTRACT
Hereditary cataracts are clinically and genetically heterogeneous lens diseases that cause a significant proportion of visual impairment and blindness in children. Human cataracts have been linked with mutations in two genes, GJA3 and GJA8, respectively. To identify the causative mutation in a family with hereditary cataracts, family members were screened for mutations by PCR for both genes. Sequencing the coding regions of GJA8, coding for connexin 50, revealed a C > A transversion at nucleotide 264, which caused p.P88T mutation. To dissect the molecular consequences of this mutation, plasmids carrying wild-type and mutant mouse ORFs of Gja8 were generated and ectopically expressed in HEK293 cells and human lens epithelial cells, respectively. The recombinant proteins were assessed by confocal microscopy and Western blotting. The results demonstrate that the molecular consequences of the p.P88T mutation in GJA8 include changes in connexin 50 protein localization patterns, accumulation of mutant protein, and increased cell growth.

Show MeSH
Related in: MedlinePlus