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Jing X, Zhu M, Lu X, Wei P, Shi L, Zhang BY, Xu Y, Tang YP, Xiang DM, Gong P. Cataract-causing Y204X mutation of crystallin protein CRYβB1 promotes its C-terminal degradation and higher-order oligomerization. J Biol Chem 2023; 299:104953. [PMID: 37356717 PMCID: PMC10382669 DOI: 10.1016/j.jbc.2023.104953] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/16/2023] [Accepted: 06/19/2023] [Indexed: 06/27/2023] Open
Abstract
Crystallin proteins are a class of main structural proteins of the vertebrate eye lens, and their solubility and stability directly determine transparency and refractive power of the lens. Mutation in genes that encode these crystallin proteins is the most common cause for congenital cataracts. Despite extensive studies, the pathogenic and molecular mechanisms that effect congenital cataracts remain unclear. In this study, we identified a novel mutation in CRYBB1 from a congenital cataract family, and demonstrated that this mutation led to an early termination of mRNA translation, resulting in a 49-residue C-terminally truncated CRYβB1 protein. We show this mutant is susceptible to proteolysis, which allowed us to determine a 1.2-Å resolution crystal structure of CRYβB1 without the entire C-terminal domain. In this crystal lattice, we observed that two N-terminal domain monomers form a dimer that structurally resembles the WT monomer, but with different surface characteristics. Biochemical analyses and cell-based data also suggested that this mutant is significantly more liable to aggregate and degrade compared to WT CRYβB1. Taken together, our results provide an insight into the mechanism regarding how a mutant crystalin contributes to the development of congenital cataract possibly through alteration of inter-protein interactions that result in protein aggregation.
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Affiliation(s)
- Xuping Jing
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China; Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Mingwei Zhu
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Xiaoyun Lu
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Ping Wei
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Lingyu Shi
- Department of Ophthalmology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Bu-Yu Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yi Xu
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Ya-Ping Tang
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China; Goungdong Key Laboratory of Structural Birth Defects, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Department of Imaging, Affiliated Hospital 3, Zhengzhou University, Zhengzhou, Henan, China.
| | - Dao-Man Xiang
- Department of Ophthalmology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China.
| | - Peng Gong
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China.
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Haploinsufficiency of EXT1 and Heparan Sulphate Deficiency Associated with Hereditary Multiple Exostoses in a Pakistani Family. Medicina (B Aires) 2022; 59:medicina59010100. [PMID: 36676722 PMCID: PMC9863873 DOI: 10.3390/medicina59010100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023] Open
Abstract
Background and Objectives: Hereditary multiple exostoses (HME) is a disease characterized by cartilage-capped bony protuberances at the site of growth plates of long bones. Functional mutations in the exostosin genes (EXT1 and EXT2) are reported to affect the hedgehog signalling pathways leading to multiple enchondromatosis. However, the exact role of each EXT protein in the regulation of heparan sulphate (HS) chain elongation is still an enigma. In this study, a Pakistani family with HME is investigated to find out the genetic basis of the disease. Materials and Methods: Genotyping of eight members of the family by amplifying microsatellite markers, tightly linked to the EXT1 and EXT2 genes. Results: The study revealed linkage of the HME family to the EXT1 locus 8q24.1. Sanger sequencing identified a heterozygous deletion (c.247Cdel) in exon 1 of EXT1, segregating with the disease phenotype in the family. In silico analysis predicted a shift in the frame causing an early stop codon (p.R83GfsX52). The predicted dwarf protein constituting 134 amino acids was functionally aberrant with a complete loss of the catalytic domain at the C-terminus. Interestingly, an alternative open reading frame 3 (ORF3) caused by the frame shift is predicted to encode a protein sequence, identical to the wild type and containing the catalytic domain, but lacking the first 100 amino acids of the wild-type EXT1 protein. Conclusion: Consequently, haploinsufficiency could be the cause of HME in the investigated family as the mutated copy of EXT1 is ineffective for EXT-1/2 complex formation. The predicted ORF3 protein could be of great significance in understanding several aspects of HME pathogenesis.
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Li X, Shi W, Ding X, Li J, Li Y, Wu J, Yuan Z, Nong T, Xu H, Zhu M. Identification of a novel TBX5 mutation in a Chinese family with rare symptoms of Holt–Oram syndrome. Heliyon 2022; 8:e11774. [DOI: 10.1016/j.heliyon.2022.e11774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/08/2022] [Accepted: 10/11/2022] [Indexed: 11/22/2022] Open
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Ren Z, Yuan JY, Zhang J, Tan Y, Chen WQ, Zhang ZT, Li YZ. Genetic analysis of seven pateints with Hereditary Multiple Osteochondromas (HMO). Am J Transl Res 2022; 14:6303-6312. [PMID: 36247276 PMCID: PMC9556467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 08/03/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND HMO (Hereditary Multiple Osteochondroma), an uncommon autosomal dominant disorder, is characterized by the development of multiple osteochondromas, which are nonmalignant cartilage-capped bone tumors growing outwards from long bone metaphyses. METHODS The present work retrospectively analyzed seven children with HMO who were enrolled for routine clinical diagnosis and treatment, including X-ray examination. Subsequent genetic detection was carried out using whole exome sequencing (WES). In addition, this work applied Sanger sequencing to be the validation approach. Moreover, this work also examined amino acid (AA) evolutionary conservatism under the influence of certain missense variants. RESULTS The clinical indications of all seven patients and their family members were thoroughly indexed. WES identified diagnostic variants in the EXT1 or EXT2 gene in these patients. In these variants, four were reported for the first time, namely EXT1: c.1285-2A>T, EXT2: c.1139delT, EXT1: c.203G>A, and EXT1: c.1645_1673del. Familial validation revealed that three of the variants were hereditary, while the other four were de novo, which was consistent with the phenotype in each case. CONCLUSION Our results expanded HMO variation spectrum, and laid certain foundations for the precise counseling of those affected families.
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Affiliation(s)
- Zhuo Ren
- Department of Obstetrics and Gynecology, Peking University International HospitalBeijing 102206, China
| | - Jia-Yu Yuan
- Department of Pediatric Orthopaedics, The Third Hospital of Hebei Medical UniversityShijiazhuang 050051, Hebei, China
| | - Jing Zhang
- Prenatal Diagnosis Center, Shijiazhuang Obstetrics and Gynecology HospitalShijiazhuang 050051, Hebei, China
- Key Laboratory of Maternal and Fetal Medicine of Hebei ProvinceShijiazhuang 050051, Hebei, China
| | - Ya Tan
- Department of Obstetrics and Gynecology, Peking University International HospitalBeijing 102206, China
| | - Wen-Qi Chen
- Prenatal Diagnosis Center, Shijiazhuang Obstetrics and Gynecology HospitalShijiazhuang 050051, Hebei, China
- Key Laboratory of Maternal and Fetal Medicine of Hebei ProvinceShijiazhuang 050051, Hebei, China
| | - Zhen-Tao Zhang
- Pain Department, The People’s Hospital of LangfangLangfang 065000, Hebei, China
| | - Ya-Zhou Li
- Department of Pediatric Orthopaedics, The Third Hospital of Hebei Medical UniversityShijiazhuang 050051, Hebei, China
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Wang W, Yang M, Shen Y, Chen K, Wu D, Yang C, Bai J, He D, Gao J. Clinical survey of a pedigree with hereditary multiple exostoses and identification of EXT‑2 gene deletion mutation. Mol Med Rep 2022; 25:141. [PMID: 35211766 PMCID: PMC8915398 DOI: 10.3892/mmr.2022.12657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/10/2022] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to report a clinical survey of hereditary multiple exostoses (HME) in a large Chinese pedigree, and the identification of a novel deletion mutation of exostosin glycosyltransferase 2 (EXT‑2) gene. A patient with multiple exostoses with huge cartilage‑capped tumors in scapula, knees and ankles received surgery in Department of Orthopedics (Shanghai Changhai Hospital). A total of 20 family members were recruited to the study, with seven members (five male; two female) diagnosed as HME. The family members of the patients with HME were examined, clinical data and peripheral blood samples were collected, and their DNA was sequenced. The incidence of HME in this family pedigree was 35%. Exostoses were most frequently in the tibiae with occurrence in six patients, followed by ribs, femurs, radii, fibulae, scapulae and humeri. DNA sequencing of peripheral blood revealed a novel deletion mutation, c.824‑826delGCA, in exon 5 of the EXT‑2 gene, which was observed in all the patients with HME, but not in the healthy family members. Several characteristics of HME in the pedigree were observed, such as susceptibility of male gender, decreased average age of onset and height and increased severity of clinical symptoms with generations.
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Affiliation(s)
- Wentao Wang
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Mingyuan Yang
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Yuhang Shen
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Kai Chen
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Donghua Wu
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Changwei Yang
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Jinyi Bai
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Dawei He
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Jun Gao
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
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Physiology and Pathophysiology of Heparan Sulfate in Animal Models: Its Biosynthesis and Degradation. Int J Mol Sci 2022; 23:ijms23041963. [PMID: 35216081 PMCID: PMC8876164 DOI: 10.3390/ijms23041963] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/05/2022] [Accepted: 02/08/2022] [Indexed: 12/17/2022] Open
Abstract
Heparan sulfate (HS) is a type of glycosaminoglycan that plays a key role in a variety of biological functions in neurology, skeletal development, immunology, and tumor metastasis. Biosynthesis of HS is initiated by a link of xylose to Ser residue of HS proteoglycans, followed by the formation of a linker tetrasaccharide. Then, an extension reaction of HS disaccharide occurs through polymerization of many repetitive units consisting of iduronic acid and N-acetylglucosamine. Subsequently, several modification reactions take place to complete the maturation of HS. The sulfation positions of N-, 2-O-, 6-O-, and 3-O- are all mediated by specific enzymes that may have multiple isozymes. C5-epimerization is facilitated by the epimerase enzyme that converts glucuronic acid to iduronic acid. Once these enzymatic reactions have been completed, the desulfation reaction further modifies HS. Apart from HS biosynthesis, the degradation of HS is largely mediated by the lysosome, an intracellular organelle with acidic pH. Mucopolysaccharidosis is a genetic disorder characterized by an accumulation of glycosaminoglycans in the body associated with neuronal, skeletal, and visceral disorders. Genetically modified animal models have significantly contributed to the understanding of the in vivo role of these enzymes. Their role and potential link to diseases are also discussed.
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Ke ZP, Zhang GF, Guo YH, Sun YM, Wang J, Li N, Qiu XB, Xu YJ, Yang YQ. A novel PRRX1 loss-of-function variation contributing to familial atrial fibrillation and congenital patent ductus arteriosus. Genet Mol Biol 2022; 45:e20210378. [PMID: 35377386 PMCID: PMC8978609 DOI: 10.1590/1678-4685-gmb-2021-0378] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/25/2022] [Indexed: 12/27/2022] Open
Abstract
Atrial fibrillation (AF) represents the most common type of sustained cardiac arrhythmia in humans and confers a significantly increased risk for thromboembolic stroke, congestive heart failure and premature death. Aggregating evidence emphasizes the predominant genetic defects underpinning AF and an increasing number of deleterious variations in more than 50 genes have been involved in the pathogenesis of AF. Nevertheless, the genetic basis underlying AF remains incompletely understood. In the current research, by whole-exome sequencing and Sanger sequencing analysis in a family with autosomal-dominant AF and congenital patent ductus arteriosus (PDA), a novel heterozygous variation in the PRRX1 gene encoding a homeobox transcription factor critical for cardiovascular development, NM_022716.4:c.373G>T;p.(Glu125*), was identified to be in co-segregation with AF and PDA in the whole family. The truncating variation was not detected in 306 unrelated healthy individuals employed as controls. Quantitative biological measurements with a reporter gene analysis system revealed that the Glu125*-mutant PRRX1 protein failed to transactivate its downstream target genes SHOX2 and ISL1, two genes that have been causally linked to AF. Conclusively, the present study firstly links PRRX1 loss-of-function variation to AF and PDA, suggesting that AF and PDA share a common abnormal developmental basis in a proportion of cases.
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Affiliation(s)
| | | | - Yu-Han Guo
- Fudan University, China; Fudan University, China
| | | | | | - Ning Li
- Shanghai Jiao Tong University, China
| | | | - Ying-Jia Xu
- Fudan University, China; Fudan University, China
| | - Yi-Qing Yang
- Fudan University, China; Fudan University, China; Fudan University, China; Fudan University, China
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