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Mohar NP, Cox EM, Adelizzi E, Moore SA, Mathews KD, Darbro BW, Wallrath LL. The Influence of a Genetic Variant in CCDC78 on LMNA-Associated Skeletal Muscle Disease. Int J Mol Sci 2024; 25:4930. [PMID: 38732148 PMCID: PMC11084688 DOI: 10.3390/ijms25094930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/12/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Mutations in the LMNA gene-encoding A-type lamins can cause Limb-Girdle muscular dystrophy Type 1B (LGMD1B). This disease presents with weakness and wasting of the proximal skeletal muscles and has a variable age of onset and disease severity. This variability has been attributed to genetic background differences among individuals; however, such variants have not been well characterized. To identify such variants, we investigated a multigeneration family in which affected individuals are diagnosed with LGMD1B. The primary genetic cause of LGMD1B in this family is a dominant mutation that activates a cryptic splice site, leading to a five-nucleotide deletion in the mature mRNA. This results in a frame shift and a premature stop in translation. Skeletal muscle biopsies from the family members showed dystrophic features of variable severity, with the muscle fibers of some family members possessing cores, regions of sarcomeric disruption, and a paucity of mitochondria, not commonly associated with LGMD1B. Using whole genome sequencing (WGS), we identified 21 DNA sequence variants that segregate with the family members possessing more profound dystrophic features and muscle cores. These include a relatively common variant in coiled-coil domain containing protein 78 (CCDC78). This variant was given priority because another mutation in CCDC78 causes autosomal dominant centronuclear myopathy-4, which causes cores in addition to centrally positioned nuclei. Therefore, we analyzed muscle biopsies from family members and discovered that those with both the LMNA mutation and the CCDC78 variant contain muscle cores that accumulated both CCDC78 and RyR1. Muscle cores containing mislocalized CCDC78 and RyR1 were absent in the less profoundly affected family members possessing only the LMNA mutation. Taken together, our findings suggest that a relatively common variant in CCDC78 can impart profound muscle pathology in combination with a LMNA mutation and accounts for variability in skeletal muscle disease phenotypes.
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Affiliation(s)
- Nathaniel P. Mohar
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA; (N.P.M.); (E.A.)
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Efrem M. Cox
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA (S.A.M.)
- Department of Neurosurgery, UNLV School of Medicine, Las Vegas, NV 89106, USA
| | - Emily Adelizzi
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA; (N.P.M.); (E.A.)
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Steven A. Moore
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA (S.A.M.)
| | - Katherine D. Mathews
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA;
| | - Benjamin W. Darbro
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA; (N.P.M.); (E.A.)
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA;
| | - Lori L. Wallrath
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA; (N.P.M.); (E.A.)
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Delineation of the Germline and Somatic Mutation Interaction Landscape in Triple-Negative and Non-Triple-Negative Breast Cancer. Int J Genomics 2020; 2020:2641370. [PMID: 32724790 PMCID: PMC7364202 DOI: 10.1155/2020/2641370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/26/2020] [Accepted: 06/09/2020] [Indexed: 11/18/2022] Open
Abstract
Background Breast cancer development and progression involve both germline and somatic mutations. High-throughput genotyping and next-generation sequencing technologies have enabled discovery of genetic risk variants and acquired somatic mutations driving the disease. However, the possible oncogenic interactions between germline genetic risk variants and somatic mutations in triple-negative breast cancer (TNBC) and non-triple-negative breast cancer (non-TNBC) have not been characterized. Here, we delineated the possible oncogenic interactions between genes containing germline and somatic mutations in TNBC and non-TNBC and investigated whether there are differences in gene expression and mutation burden between the two types of breast cancer. Methods We addressed this problem by integrating germline mutation information from genome-wide association studies with somatic mutation information from next-generation sequencing using gene expression data as the intermediated phenotype. We performed network and pathway analyses to discover molecular networks and signalling pathways enriched for germline and somatic mutations. Results The investigation revealed signatures of differentially expressed and differentially somatic mutated genes between TNBC and non-TNBC. Network and pathway analyses revealed functionally related genes interacting in gene regulatory networks and multiple signalling pathways enriched for germline and somatic mutations for each type of breast cancer. Among the signalling pathways discovered included the DNA repair and Androgen and ATM signalling pathways for TNBC and the DNA damage response, molecular mechanisms of cancer, and ATM and GP6 signalling pathways for non-TNBC. Conclusions The results show that integrative genomics is a powerful approach for delineating oncogenic interactions between genes containing germline and genes containing somatic mutations in TNBC and non-TNBC and establishes putative functional bridges between genetic and somatic alterations and the pathways they control in the two types of breast cancer.
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Mamidi TKK, Wu J, Hicks C. Mapping the Germline and Somatic Mutation Interaction Landscape in Indolent and Aggressive Prostate Cancers. JOURNAL OF ONCOLOGY 2019; 2019:4168784. [PMID: 31814827 PMCID: PMC6878815 DOI: 10.1155/2019/4168784] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND A majority of prostate cancers (PCas) are indolent and cause no harm even without treatment. However, a significant proportion of patients with PCa have aggressive tumors that progress rapidly to metastatic disease and are often lethal. PCa develops through somatic mutagenesis, but emerging evidence suggests that germline genetic variation can markedly contribute to tumorigenesis. However, the causal association between genetic susceptibility and tumorigenesis has not been well characterized. The objective of this study was to map the germline and somatic mutation interaction landscape in indolent and aggressive tumors and to discover signatures of mutated genes associated with each type and distinguishing the two types of PCa. MATERIALS AND METHODS We integrated germline mutation information from genome-wide association studies (GWAS) with somatic mutation information from The Cancer Genome Atlas (TCGA) using gene expression data from TCGA on indolent and aggressive PCas as the intermediate phenotypes. Germline and somatic mutated genes associated with each type of PCa were functionally characterized using network and pathway analysis. RESULTS We discovered gene signatures containing germline and somatic mutations associated with each type and distinguishing the two types of PCa. We discovered multiple gene regulatory networks and signaling pathways enriched with germline and somatic mutations including axon guidance, RAR, WINT, MSP-RON, STAT3, PI3K, TR/RxR, and molecular mechanisms of cancer, NF-kB, prostate cancer, GP6, androgen, and VEGF signaling pathways for indolent PCa and MSP-RON, axon guidance, RAR, adipogenesis, and molecular mechanisms of cancer and NF-kB signaling pathways for aggressive PCa. CONCLUSION The investigation revealed germline and somatic mutated genes associated with indolent and aggressive PCas and distinguishing the two types of PCa. The study revealed multiple gene regulatory networks and signaling pathways dysregulated by germline and somatic alterations. Integrative analysis combining germline and somatic mutations is a powerful approach to mapping germline and somatic mutation interaction landscape.
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Affiliation(s)
- Tarun Karthik Kumar Mamidi
- Informatics Institute, University of Alabama at Birmingham, School of Medicine, 1720 2nd Avenue South, Birmingham, AL 35294-3412, USA
| | - Jiande Wu
- Department of Genetics, Louisiana State University Health Sciences Center, School of Medicine, 533 Bolivar, New Orleans, LA-70112, USA
| | - Chindo Hicks
- Department of Genetics, Louisiana State University Health Sciences Center, School of Medicine, 533 Bolivar, New Orleans, LA-70112, USA
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Karam R, Conner B, LaDuca H, McGoldrick K, Krempely K, Richardson ME, Zimmermann H, Gutierrez S, Reineke P, Hoang L, Allen K, Yussuf A, Farber-Katz S, Rana HQ, Culver S, Lee J, Nashed S, Toppmeyer D, Collins D, Haynes G, Pesaran T, Dolinsky JS, Tippin Davis B, Elliott A, Chao E. Assessment of Diagnostic Outcomes of RNA Genetic Testing for Hereditary Cancer. JAMA Netw Open 2019; 2:e1913900. [PMID: 31642931 PMCID: PMC6820040 DOI: 10.1001/jamanetworkopen.2019.13900] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
IMPORTANCE Performing DNA genetic testing (DGT) for hereditary cancer genes is now a well-accepted clinical practice; however, the interpretation of DNA variation remains a challenge for laboratories and clinicians. Adding RNA genetic testing (RGT) enhances DGT by clarifying the clinical actionability of hereditary cancer gene variants, thus improving clinicians' ability to accurately apply strategies for cancer risk reduction and treatment. OBJECTIVE To evaluate whether RGT is associated with improvement in the diagnostic outcome of DGT and in the delivery of personalized cancer risk management for patients with hereditary cancer predisposition. DESIGN, SETTING, AND PARTICIPANTS Diagnostic study in which patients and/or families with inconclusive variants detected by DGT in genes associated with hereditary breast and ovarian cancer, Lynch syndrome, and hereditary diffuse gastric cancer sent blood samples for RGT from March 2016 to April 2018. Clinicians who ordered genetic testing and received a reclassification report for these variants were surveyed to assess whether RGT-related variant reclassifications changed clinical management of these patients. To quantify the potential number of tested individuals who could benefit from RGT, a cohort of 307 812 patients who underwent DGT for hereditary cancer were separately queried to identify variants predicted to affect splicing. Data analysis was conducted from March 2016 and September 2018. MAIN OUTCOMES AND MEASURES Variant reclassification outcomes following RGT, clinical management changes associated with RGT-related variant reclassifications, and the proportion of patients who would likely be affected by a concurrent DGT and RGT multigene panel testing approach. RESULTS In total, 93 if 909 eligible families (10.2%) submitted samples for RGT. Evidence from RGT clarified the interpretation of 49 of 56 inconclusive cases (88%) studied; 26 (47%) were reclassified as clinically actionable and 23 (41%) were clarified as benign. Variant reclassifications based on RGT results changed clinical management recommendations for 8 of 18 patients (44%) and 14 of 18 families (78%), based on responses from 18 of 45 clinicians (40%) surveyed. A total of 7265 of 307 812 patients who underwent DGT had likely pathogenic variants or variants of uncertain significance potentially affecting splicing, indicating that approximately 1 in 43 individuals could benefit from RGT. CONCLUSIONS AND RELEVANCE In this diagnostic study, conducting RNA testing resolved a substantial proportion of variants of uncertain significance in a cohort of individuals previously tested for cancer predisposition by DGT. Performing RGT might change the diagnostic outcome of at least 1 in 43 patients if performed in all individuals undergoing genetic evaluation for hereditary cancer.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Suzette Farber-Katz
- Ambry Genetics, Aliso Viejo, California
- now with Merck Research Laboratories, South San Francisco, California
| | - Huma Q. Rana
- Department of Medicine, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Samantha Culver
- Department of Medicine, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - John Lee
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Sarah Nashed
- Division of Medical Oncology, Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick
| | - Deborah Toppmeyer
- Division of Medical Oncology, Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick
| | | | | | | | | | | | | | - Elizabeth Chao
- Ambry Genetics, Aliso Viejo, California
- Department of Pediatrics, School of Medicine, University of California, Irvine
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Mascarenhas JB, Tchourbanov AY, Danilov SM, Zhou T, Wang T, Garcia JGN. The Splicing Factor hnRNPA1 Regulates Alternate Splicing of the MYLK Gene. Am J Respir Cell Mol Biol 2019; 58:604-613. [PMID: 29077485 DOI: 10.1165/rcmb.2017-0141oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Profound lung vascular permeability is a cardinal feature of acute respiratory distress syndrome (ARDS) and ventilator-induced lung injury (VILI), two syndromes known to centrally involve the nonmuscle isoform of myosin light chain kinase (nmMLCK) in vascular barrier dysregulation. Two main splice variants, nmMLCK1 and nmMLCK2, are well represented in human lung endothelial cells and encoded by MYLK, and they differ only in the presence of exon 11 in nmMLCK1, which contains critical phosphorylation sites (Y464 and Y471) that influence nmMLCK enzymatic activity, cellular translocation, and localization in response to vascular agonists. We recently demonstrated the functional role of SNPs in altering MYLK splicing, and in the present study we sought to identify the role of splicing factors in the generation of nmMLCK1 and nmMLCK2 spliced variants. Using bioinformatic in silico approaches, we identified a putative binding site for heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), a recognized splicing factor. We verified hnRNPA1 binding to MYLK by gel shift analyses and that hnRNPA1 gene and protein expression is upregulated in mouse lungs obtained from preclinical models of ARDS and VILI and in human endothelial cells exposed to 18% cyclic stretch, a model that reproduces the excessive mechanical stress observed in VILI. Using an MYLK minigene approach, we established a direct role of hnRNPA1 in MYLK splicing and in the context of 18% cyclic stretch. In summary, these data indicate an important regulatory role for hnRNPA1 in MYLK splicing, and they increase understanding of MYLK splicing in the regulation of lung vascular integrity during acute lung inflammation and excessive mechanical stress, such as that observed in ARDS and VILI.
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Affiliation(s)
| | | | - Sergei M Danilov
- 1 Department of Medicine, College of Medicine, and.,3 Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois; and
| | - Tong Zhou
- 4 Department of Physiology and Cell Biology, The University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Ting Wang
- 1 Department of Medicine, College of Medicine, and
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Wu J, Mamidi TKK, Zhang L, Hicks C. Integrating Germline and Somatic Mutation Information for the Discovery of Biomarkers in Triple-Negative Breast Cancer. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16061055. [PMID: 30909550 PMCID: PMC6466377 DOI: 10.3390/ijerph16061055] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 12/22/2022]
Abstract
Recent advances in high-throughput genotyping and the recent surge of next generation sequencing of the cancer genomes have enabled discovery of germline mutations associated with an increased risk of developing breast cancer and acquired somatic mutations driving the disease. Emerging evidence indicates that germline mutations may interact with somatic mutations to drive carcinogenesis. However, the possible oncogenic interactions and cooperation between germline and somatic alterations in triple-negative breast cancer (TNBC) have not been characterized. The objective of this study was to investigate the possible oncogenic interactions and cooperation between genes containing germline and somatic mutations in TNBC. Our working hypothesis was that genes containing germline mutations associated with an increased risk developing breast cancer also harbor somatic mutations acquired during tumorigenesis, and that these genes are functionally related. We further hypothesized that TNBC originates from a complex interplay among and between genes containing germline and somatic mutations, and that these complex array of interacting genetic factors affect entire molecular networks and biological pathways which in turn drive the disease. We tested this hypothesis by integrating germline mutation information from genome-wide association studies (GWAS) with somatic mutation information on TNBC from The Cancer Genome Atlas (TCGA) using gene expression data from 110 patients with TNBC and 113 controls. We discovered a signature of 237 functionally related genes containing both germline and somatic mutations. We discovered molecular networks and biological pathways enriched for germline and somatic mutations. The top pathways included the hereditary breast cancer and role of BRCA1 in DNA damage response signaling pathways. In conclusion, this is the first large-scale and comprehensive analysis delineating possible oncogenic interactions and cooperation among and between genes containing germline and somatic mutations in TNBC. Genetic and somatic mutations, along with the genes discovered in this study, will require experimental functional validation in different ethnic populations. Functionally validated genetic and somatic variants will have important implications for the development of novel precision prevention strategies and discovery of prognostic markers in TNBC.
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Affiliation(s)
- Jiande Wu
- Department of Genetics and the Bioinformatics and Genomics Program, Louisiana State University Health Sciences Center, School of Medicine, 533 Bolivar Street, New Orleans, LA 70112, USA.
| | - Tarun Karthik Kumar Mamidi
- Department of Genetics and the Bioinformatics and Genomics Program, Louisiana State University Health Sciences Center, School of Medicine, 533 Bolivar Street, New Orleans, LA 70112, USA.
| | - Lu Zhang
- Louisiana Tumor Registry, Louisiana State University Health Sciences Center, School of Public Health, 2020 Gravier Street, New Orleans, LA 70112, USA.
| | - Chindo Hicks
- Department of Genetics and the Bioinformatics and Genomics Program, Louisiana State University Health Sciences Center, School of Medicine, 533 Bolivar Street, New Orleans, LA 70112, USA.
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Splicing mutation analysis reveals previously unrecognized pathways in lymph node-invasive breast cancer. Sci Rep 2014; 4:7063. [PMID: 25394353 PMCID: PMC4231324 DOI: 10.1038/srep07063] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/29/2014] [Indexed: 12/22/2022] Open
Abstract
Somatic mutations reported in large-scale breast cancer (BC) sequencing studies primarily consist of protein coding mutations. mRNA splicing mutation analyses have been limited in scope, despite their prevalence in Mendelian genetic disorders. We predicted splicing mutations in 442 BC tumour and matched normal exomes from The Cancer Genome Atlas Consortium (TCGA). These splicing defects were validated by abnormal expression changes in these tumours. Of the 5,206 putative mutations identified, exon skipping, leaky or cryptic splicing was confirmed for 988 variants. Pathway enrichment analysis of the mutated genes revealed mutations in 9 NCAM1-related pathways, which were significantly increased in samples with evidence of lymph node metastasis, but not in lymph node-negative tumours. We suggest that comprehensive reporting of DNA sequencing data should include non-trivial splicing analyses to avoid missing clinically-significant deleterious splicing mutations, which may reveal novel mutated pathways present in genetic disorders.
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Viner C, Dorman SN, Shirley BC, Rogan PK. Validation of predicted mRNA splicing mutations using high-throughput transcriptome data. F1000Res 2014; 3:8. [PMID: 24741438 PMCID: PMC3983938 DOI: 10.12688/f1000research.3-8.v2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/03/2014] [Indexed: 01/20/2023] Open
Abstract
Interpretation of variants present in complete genomes or exomes reveals numerous sequence changes, only a fraction of which are likely to be pathogenic. Mutations have been traditionally inferred from allele frequencies and inheritance patterns in such data. Variants predicted to alter mRNA splicing can be validated by manual inspection of transcriptome sequencing data, however this approach is intractable for large datasets. These abnormal mRNA splicing patterns are characterized by reads demonstrating either exon skipping, cryptic splice site use, and high levels of intron inclusion, or combinations of these properties. We present, Veridical, an
in silico method for the automatic validation of DNA sequencing variants that alter mRNA splicing. Veridical performs statistically valid comparisons of the normalized read counts of abnormal RNA species in mutant versus non-mutant tissues. This leverages large numbers of control samples to corroborate the consequences of predicted splicing variants in complete genomes and exomes.
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Affiliation(s)
- Coby Viner
- Department of Computer Science, University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Stephanie N Dorman
- Department of Biochemistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | | | - Peter K Rogan
- Department of Computer Science, University of Western Ontario, London, Ontario, N6A 5B7, Canada ; Department of Biochemistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada ; Cytognomix, Inc., London, Ontario, N6G 4X8, Canada
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9
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Abstract
Interpretation of variants present in complete genomes or exomes reveals numerous sequence changes, only a fraction of which are likely to be pathogenic. Mutations have been traditionally inferred from allele frequencies and inheritance patterns in such data. Variants predicted to alter mRNA splicing can be validated by manual inspection of transcriptome sequencing data, however this approach is intractable for large datasets. These abnormal mRNA splicing patterns are characterized by reads demonstrating either exon skipping, cryptic splice site use, and high levels of intron inclusion, or combinations of these properties. We present, Veridical, an in silico method for the automatic validation of DNA sequencing variants that alter mRNA splicing. Veridical performs statistically valid comparisons of the normalized read counts of abnormal RNA species in mutant versus non-mutant tissues. This leverages large numbers of control samples to corroborate the consequences of predicted splicing variants in complete genomes and exomes.
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Affiliation(s)
- Coby Viner
- Department of Computer Science, University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Stephanie N Dorman
- Department of Biochemistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | | | - Peter K Rogan
- Department of Computer Science, University of Western Ontario, London, Ontario, N6A 5B7, Canada ; Department of Biochemistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada ; Cytognomix, Inc., London, Ontario, N6G 4X8, Canada
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Persu A, Lambert M, Deinum J, Cossu M, de Visscher N, Irenge L, Ambroise J, Minon JM, Nesterovitch AB, Churbanov A, Popova IA, Danilov SM, Danser AHJ, Gala JL. A novel splice-site mutation in angiotensin I-converting enzyme (ACE) gene, c.3691+1G>A (IVS25+1G>A), causes a dramatic increase in circulating ACE through deletion of the transmembrane anchor. PLoS One 2013; 8:e59537. [PMID: 23560051 PMCID: PMC3613373 DOI: 10.1371/journal.pone.0059537] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/15/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Angiotensin-converting enzyme (ACE) (EC 4.15.1) metabolizes many biologically active peptides and plays a key role in blood pressure regulation and vascular remodeling. Elevated ACE levels are associated with different cardiovascular and respiratory diseases. METHODS AND RESULTS Two Belgian families with a 8-16-fold increase in blood ACE level were incidentally identified. A novel heterozygous splice site mutation of intron 25 - IVS25+1G>A (c.3691+1G>A) - cosegregating with elevated plasma ACE was identified in both pedigrees. Messenger RNA analysis revealed that the mutation led to the retention of intron 25 and Premature Termination Codon generation. Subjects harboring the mutation were mostly normotensive, had no left ventricular hypertrophy or cardiovascular disease. The levels of renin-angiotensin-aldosterone system components in the mutated cases and wild-type controls were similar, both at baseline and after 50 mg captopril. Compared with non-affected members, quantification of ACE surface expression and shedding using flow cytometry assay of dendritic cells derived from peripheral blood monocytes of affected members, demonstrated a 50% decrease and 3-fold increase, respectively. Together with a dramatic increase in circulating ACE levels, these findings argue in favor of deletion of transmembrane anchor, leading to direct secretion of ACE out of cells. CONCLUSIONS We describe a novel mutation of the ACE gene associated with a major familial elevation of circulating ACE, without evidence of activation of the renin-angiotensin system, target organ damage or cardiovascular complications. These data are consistent with the hypothesis that membrane-bound ACE, rather than circulating ACE, is responsible for Angiotensin II generation and its cardiovascular consequences.
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Affiliation(s)
- Alexandre Persu
- Pole of Cardiovascular Research, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.
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11
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Shirley BC, Mucaki EJ, Whitehead T, Costea PI, Akan P, Rogan PK. Interpretation, stratification and evidence for sequence variants affecting mRNA splicing in complete human genome sequences. GENOMICS PROTEOMICS & BIOINFORMATICS 2013; 11:77-85. [PMID: 23499923 PMCID: PMC4357664 DOI: 10.1016/j.gpb.2013.01.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 01/16/2013] [Accepted: 01/21/2013] [Indexed: 11/29/2022]
Abstract
Information theory-based methods have been shown to be sensitive and specific for predicting and quantifying the effects of non-coding mutations in Mendelian diseases. We present the Shannon pipeline software for genome-scale mutation analysis and provide evidence that the software predicts variants affecting mRNA splicing. Individual information contents (in bits) of reference and variant splice sites are compared and significant differences are annotated and prioritized. The software has been implemented for CLC-Bio Genomics platform. Annotation indicates the context of novel mutations as well as common and rare SNPs with splicing effects. Potential natural and cryptic mRNA splicing variants are identified, and null mutations are distinguished from leaky mutations. Mutations and rare SNPs were predicted in genomes of three cancer cell lines (U2OS, U251 and A431), which were supported by expression analyses. After filtering, tractable numbers of potentially deleterious variants are predicted by the software, suitable for further laboratory investigation. In these cell lines, novel functional variants comprised 6–17 inactivating mutations, 1–5 leaky mutations and 6–13 cryptic splicing mutations. Predicted effects were validated by RNA-seq analysis of the three aforementioned cancer cell lines, and expression microarray analysis of SNPs in HapMap cell lines.
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Affiliation(s)
- Ben C Shirley
- Department of Computer Science, Middlesex College, The University of Western Ontario, London, ON N6A 5B7, Canada
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12
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Rawal HC, Singh NK, Sharma TR. Conservation, Divergence, and Genome-Wide Distribution of PAL and POX A Gene Families in Plants. Int J Genomics 2013; 2013:678969. [PMID: 23671845 PMCID: PMC3647544 DOI: 10.1155/2013/678969] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/04/2013] [Accepted: 01/11/2013] [Indexed: 01/03/2023] Open
Abstract
Genome-wide identification and phylogenetic and syntenic comparison were performed for the genes responsible for phenylalanine ammonia lyase (PAL) and peroxidase A (POX A) enzymes in nine plant species representing very diverse groups like legumes (Glycine max and Medicago truncatula), fruits (Vitis vinifera), cereals (Sorghum bicolor, Zea mays, and Oryza sativa), trees (Populus trichocarpa), and model dicot (Arabidopsis thaliana) and monocot (Brachypodium distachyon) species. A total of 87 and 1045 genes in PAL and POX A gene families, respectively, have been identified in these species. The phylogenetic and syntenic comparison along with motif distributions shows a high degree of conservation of PAL genes, suggesting that these genes may predate monocot/eudicot divergence. The POX A family genes, present in clusters at the subtelomeric regions of chromosomes, might be evolving and expanding with higher rate than the PAL gene family. Our analysis showed that during the expansion of POX A gene family, many groups and subgroups have evolved, resulting in a high level of functional divergence among monocots and dicots. These results will act as a first step toward the understanding of monocot/eudicot evolution and functional characterization of these gene families in the future.
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Affiliation(s)
| | | | - T. R. Sharma
- Genoinformatics Laboratory, National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute, Pusa Campus, New Delhi 110 012, India
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Worsley-Hunt R, Bernard V, Wasserman WW. Identification of cis-regulatory sequence variations in individual genome sequences. Genome Med 2011; 3:65. [PMID: 21989199 PMCID: PMC3239227 DOI: 10.1186/gm281] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Functional contributions of cis-regulatory sequence variations to human genetic disease are numerous. For instance, disrupting variations in a HNF4A transcription factor binding site upstream of the Factor IX gene contributes causally to hemophilia B Leyden. Although clinical genome sequence analysis currently focuses on the identification of protein-altering variation, the impact of cis-regulatory mutations can be similarly strong. New technologies are now enabling genome sequencing beyond exomes, revealing variation across the non-coding 98% of the genome responsible for developmental and physiological patterns of gene activity. The capacity to identify causal regulatory mutations is improving, but predicting functional changes in regulatory DNA sequences remains a great challenge. Here we explore the existing methods and software for prediction of functional variation situated in the cis-regulatory sequences governing gene transcription and RNA processing.
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Affiliation(s)
- Rebecca Worsley-Hunt
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada.
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14
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Hicks C, Asfour R, Pannuti A, Miele L. An integrative genomics approach to biomarker discovery in breast cancer. Cancer Inform 2011; 10:185-204. [PMID: 21869864 PMCID: PMC3153161 DOI: 10.4137/cin.s6837] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Genome-wide association studies (GWAS) have successfully identified genetic variants associated with risk for breast cancer. However, the molecular mechanisms through which the identified variants confer risk or influence phenotypic expression remains poorly understood. Here, we present a novel integrative genomics approach that combines GWAS information with gene expression data to assess the combined contribution of multiple genetic variants acting within genes and putative biological pathways, and to identify novel genes and biological pathways that could not be identified using traditional GWAS. The results show that genes containing SNPs associated with risk for breast cancer are functionally related and interact with each other in biological pathways relevant to breast cancer. Additionally, we identified novel genes that are co-expressed and interact with genes containing SNPs associated with breast cancer. Integrative analysis combining GWAS information with gene expression data provides functional bridges between GWAS findings and biological pathways involved in breast cancer.
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Affiliation(s)
- Chindo Hicks
- Cancer Institute, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS, USA
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15
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Genome-wide prediction of splice-modifying SNPs in human genes using a new analysis pipeline called AASsites. BMC Bioinformatics 2011; 12 Suppl 4:S2. [PMID: 21992029 PMCID: PMC3194194 DOI: 10.1186/1471-2105-12-s4-s2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background Some single nucleotide polymorphisms (SNPs) are known to modify the risk of developing certain diseases or the reaction to drugs. Due to next generation sequencing methods the number of known human SNPs has grown. Not all SNPs lead to a modified protein, which may be the origin of a disease. Therefore, the recognition of functional SNPs is needed. Because most SNP annotation tools look for SNPs which lead to an amino acid exchange or a premature stop, we designed a new tool called AASsites which searches for SNPs which modify splicing. Results AASsites uses several gene prediction programs and open reading frame prediction to compare the wild type (wt) and the variant gene sequence. The results of the comparison are combined by a handmade rule system to classify a change in splicing as “likely, probable, unlikely”. Having received good results from tests with SNPs known for changing the splicing pattern we checked 80,000 SNPs from the human genome which are located near splice sites for their ability to change the splicing pattern of the gene and hereby result in a different protein. We identified 301 “likely” and 985 “probable” classified SNPs with such characteristics. Within this set 33 SNPs are described in the ssSNP Target database to cause modified splicing. Conclusions With AASsites single SNPs can be checked for those causing splice modifications. Screening 80,000 known human SNPs we detected about 1,200 SNPs which probably modify splicing. AASsites is available at http://genius.embnet.dkfz-heidelberg.de/menu/biounit/open-husar using any web browser.
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16
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Kralovicova J, Hwang G, Asplund AC, Churbanov A, Smith CIE, Vorechovsky I. Compensatory signals associated with the activation of human GC 5' splice sites. Nucleic Acids Res 2011; 39:7077-91. [PMID: 21609956 PMCID: PMC3167603 DOI: 10.1093/nar/gkr306] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
GC 5′ splice sites (5′ss) are present in ∼1% of human introns, but factors promoting their efficient selection are poorly understood. Here, we describe a case of X-linked agammaglobulinemia resulting from a GC 5′ss activated by a mutation in BTK intron 3. This GC 5′ss was intrinsically weak, yet it was selected in >90% primary transcripts in the presence of a strong and intact natural GT counterpart. We show that efficient selection of this GC 5′ss required a high density of GAA/CAA-containing splicing enhancers in the exonized segment and was promoted by SR proteins 9G8, Tra2β and SC35. The GC 5′ss was efficiently inhibited by splice-switching oligonucleotides targeting either the GC 5′ss itself or the enhancer. Comprehensive analysis of natural GC-AG introns and previously reported pathogenic GC 5′ss showed that their efficient activation was facilitated by higher densities of splicing enhancers and lower densities of silencers than their GT 5′ss equivalents. Removal of the GC-AG introns was promoted to a minor extent by the splice-site strength of adjacent exons and inhibited by flanking Alu repeats, with the first downstream Alus located on average at a longer distance from the GC 5′ss than other transposable elements. These results provide new insights into the splicing code that governs selection of noncanonical splice sites.
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Affiliation(s)
- Jana Kralovicova
- University of Southampton School of Medicine, Division of Human Genetics, Southampton SO16 6YD, UK
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