15 results on '"Schwab TL"'
Search Results
2. Nuclear Abnormalities in LMNA p.(Glu2Lys) Variant Segregating with LMNA -Associated Cardiocutaneous Progeria Syndrome.
- Author
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Wilke MVMB, Wick M, Schwab TL, Starosta RT, Clark KJ, Connolly HM, and Klee EW
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- Female, Humans, Adult, Lamin Type A genetics, Cell Line, Intermediate Filament Proteins, Progeria genetics, Cardiomyopathies, Cardiomyopathy, Dilated genetics
- Abstract
The LMNA gene encodes lamin A and lamin C, which play important roles in nuclear organization. Pathogenic variants in LMNA cause laminopathies, a group of disorders with diverse phenotypes. There are two main groups of disease-causing variants: missense variants affecting dimerization and intermolecular interactions, and heterozygous substitutions activating cryptic splice sites. These variants lead to different disorders, such as dilated cardiomyopathy and Hutchinson-Gilford progeria (HGP). Among these, the phenotypic terms for LMNA -associated cardiocutaneous progeria syndrome (LCPS), which does not alter lamin A processing and has an older age of onset, have been described. Here, we present the workup of an LMNA variant of uncertain significance, NM_170707.2 c. 4G>A, p.(Glu2Lys), in a 36-year-old female with severe calcific aortic stenosis, a calcified mitral valve, premature aging, and a family history of similar symptoms. Due to the uncertainty of in silico predictions for this variant, an assessment of nuclear morphology was performed using the immunocytochemistry of stable cell lines to indicate whether the p.(Glu2Lys) had a similar pathogenic mechanism as a previously described pathogenic variant associated with LCPS, p.Asp300Gly. Indirect immunofluorescence analysis of nuclei from stable cell lines showed abnormal morphology, including lobulation and occasional ringed nuclei. Relative to the controls, p.Glu2Lys and p.Asp300Gly nuclei had significantly ( p < 0.001) smaller average nuclear areas than controls (mean = 0.10 units, SD = 0.06 for p.Glu2Lys; and mean = 0.09 units, SD = 0.05 for p.Asp300Gly versus mean = 0.12, SD = 0.05 for WT). After functional studies and segregation studies, this variant was upgraded to likely pathogenic. In summary, our findings suggest that p.Glu2Lys impacts nuclear morphology in a manner comparable to what was observed in p.Asp300Gly cells, indicating that the variant is the likely cause of the LCPS segregating within this family.
- Published
- 2024
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3. Bi-allelic variants in HMGCR cause an autosomal-recessive progressive limb-girdle muscular dystrophy.
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Morales-Rosado JA, Schwab TL, Macklin-Mantia SK, Foley AR, Pinto E Vairo F, Pehlivan D, Donkervoort S, Rosenfeld JA, Boyum GE, Hu Y, Cong ATQ, Lotze TE, Mohila CA, Saade D, Bharucha-Goebel D, Chao KR, Grunseich C, Bruels CC, Littel HR, Estrella EA, Pais L, Kang PB, Zimmermann MT, Lupski JR, Lee B, Schellenberg MJ, Clark KJ, Wierenga KJ, Bönnemann CG, and Klee EW
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- Humans, Mevalonic Acid, Oxidoreductases, Hydroxymethylglutaryl CoA Reductases genetics, Hydroxymethylglutaryl CoA Reductases adverse effects, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Muscular Dystrophies, Limb-Girdle genetics, Muscular Dystrophies, Limb-Girdle diagnosis, Muscular Diseases genetics, Muscular Dystrophies
- Abstract
Statins are a mainstay intervention for cardiovascular disease prevention, yet their use can cause rare severe myopathy. HMG-CoA reductase, an essential enzyme in the mevalonate pathway, is the target of statins. We identified nine individuals from five unrelated families with unexplained limb-girdle like muscular dystrophy and bi-allelic variants in HMGCR via clinical and research exome sequencing. The clinical features resembled other genetic causes of muscular dystrophy with incidental high CPK levels (>1,000 U/L), proximal muscle weakness, variable age of onset, and progression leading to impaired ambulation. Muscle biopsies in most affected individuals showed non-specific dystrophic changes with non-diagnostic immunohistochemistry. Molecular modeling analyses revealed variants to be destabilizing and affecting protein oligomerization. Protein activity studies using three variants (p.Asp623Asn, p.Tyr792Cys, and p.Arg443Gln) identified in affected individuals confirmed decreased enzymatic activity and reduced protein stability. In summary, we showed that individuals with bi-allelic amorphic (i.e., null and/or hypomorphic) variants in HMGCR display phenotypes that resemble non-genetic causes of myopathy involving this reductase. This study expands our knowledge regarding the mechanisms leading to muscular dystrophy through dysregulation of the mevalonate pathway, autoimmune myopathy, and statin-induced myopathy., Competing Interests: Declaration of interests The Department of Molecular and Human Genetics at Baylor College of Medicine receives revenue from clinical genetic testing from Baylor Genetics Laboratories. J.R.L. has stock ownership in 23andMe, is a paid consultant for Regeneron Pharmaceuticals, and is a co-inventor on multiple United States and European patents related to molecular diagnostics for inherited neuropathies, eye diseases, genomic disorders, and bacterial genomic fingerprinting., (Copyright © 2023. Published by Elsevier Inc.)
- Published
- 2023
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4. Impact of integrated translational research on clinical exome sequencing.
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Klee EW, Cousin MA, Pinto E Vairo F, Morales-Rosado JA, Macke EL, Jenkinson WG, Ferrer A, Schultz-Rogers LE, Olson RJ, Oliver GR, Sigafoos AN, Schwab TL, Zimmermann MT, Urrutia RA, Kaiwar C, Gupta A, Blackburn PR, Boczek NJ, Prochnow CA, Lowy RJ, Mulvihill LA, McAllister TM, Aoudia SL, Kruisselbrink TM, Gunderson LB, Kemppainen JL, Fisher LJ, Tarnowski JM, Hager MM, Kroc SA, Bertsch NL, Agre KE, Jackson JL, Macklin-Mantia SK, Murphree MI, Rust LM, Summer Bolster JM, Beck SA, Atwal PS, Ellingson MS, Barnett SS, Rasmussen KJ, Lahner CA, Niu Z, Hasadsri L, Ferber MJ, Marcou CA, Clark KJ, Pichurin PN, Deyle DR, Morava-Kozicz E, Gavrilova RH, Dhamija R, Wierenga KJ, Lanpher BC, Babovic-Vuksanovic D, Farrugia G, Schimmenti LA, Stewart AK, and Lazaridis KN
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- 2023
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5. A Primer Genetic Toolkit for Exploring Mitochondrial Biology and Disease Using Zebrafish.
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Sabharwal A, Campbell JM, Schwab TL, WareJoncas Z, Wishman MD, Ata H, Liu W, Ichino N, Hunter DE, Bergren JD, Urban MD, Urban RM, Holmberg SR, Kar B, Cook A, Ding Y, Xu X, Clark KJ, and Ekker SC
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- Animals, Genes, Mitochondrial, Humans, Mitochondria genetics, Mitochondria metabolism, Genome, Mitochondrial, Zebrafish genetics, Zebrafish metabolism
- Abstract
Mitochondria are a dynamic eukaryotic innovation that play diverse roles in biology and disease. The mitochondrial genome is remarkably conserved in all vertebrates, encoding the same 37-gene set and overall genomic structure, ranging from 16,596 base pairs (bp) in the teleost zebrafish ( Danio rerio ) to 16,569 bp in humans. Mitochondrial disorders are amongst the most prevalent inherited diseases, affecting roughly 1 in every 5000 individuals. Currently, few effective treatments exist for those with mitochondrial ailments, representing a major unmet patient need. Mitochondrial dysfunction is also a common component of a wide variety of other human illnesses, ranging from neurodegenerative disorders such as Huntington's disease and Parkinson's disease to autoimmune illnesses such as multiple sclerosis and rheumatoid arthritis. The electron transport chain (ETC) component of mitochondria is critical for mitochondrial biology and defects can lead to many mitochondrial disease symptoms. Here, we present a publicly available collection of genetic mutants created in highly conserved, nuclear-encoded mitochondrial genes in Danio rerio . The zebrafish system represents a potentially powerful new opportunity for the study of mitochondrial biology and disease due to the large number of orthologous genes shared with humans and the many advanced features of this model system, from genetics to imaging. This collection includes 15 mutant lines in 13 different genes created through locus-specific gene editing to induce frameshift or splice acceptor mutations, leading to predicted protein truncation during translation. Additionally, included are 11 lines created by the random insertion of the gene-breaking transposon (GBT) protein trap cassette. All these targeted mutant alleles truncate conserved domains of genes critical to the proper function of the ETC or genes that have been implicated in human mitochondrial disease. This collection is designed to accelerate the use of zebrafish to study many different aspects of mitochondrial function to widen our understanding of their role in biology and human disease.
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- 2022
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6. Designed architectural proteins that tune DNA looping in bacteria.
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Tse DH, Becker NA, Young RT, Olson WK, Peters JP, Schwab TL, Clark KJ, and Maher LJ
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- Gene Expression Regulation, Bacterial, Lac Operon, Nucleic Acid Conformation, Promoter Regions, Genetic, Protein Binding, DNA, Bacterial metabolism, DNA-Binding Proteins metabolism, Escherichia coli genetics, Escherichia coli Proteins metabolism
- Abstract
Architectural proteins alter the shape of DNA. Some distort the double helix by introducing sharp kinks. This can serve to relieve strain in tightly-bent DNA structures. Here, we design and test artificial architectural proteins based on a sequence-specific Transcription Activator-like Effector (TALE) protein, either alone or fused to a eukaryotic high mobility group B (HMGB) DNA-bending domain. We hypothesized that TALE protein binding would stiffen DNA to bending and twisting, acting as an architectural protein that antagonizes the formation of small DNA loops. In contrast, fusion to an HMGB domain was hypothesized to generate a targeted DNA-bending architectural protein that facilitates DNA looping. We provide evidence from Escherichia coli Lac repressor gene regulatory loops supporting these hypotheses in living bacteria. Both data fitting to a thermodynamic DNA looping model and sophisticated molecular modeling support the interpretation of these results. We find that TALE protein binding inhibits looping by stiffening DNA to bending and twisting, while the Nhp6A domain enhances looping by bending DNA without introducing twisting flexibility. Our work illustrates artificial approaches to sculpt DNA geometry with functional consequences. Similar approaches may be applicable to tune the stability of small DNA loops in eukaryotes., (© The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2021
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7. A homozygous missense variant in UBE2T is associated with a mild Fanconi anemia phenotype.
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Schultz-Rogers L, Lach FP, Rickman KA, Ferrer A, Mangaonkar AA, Schwab TL, Schmitz CT, Clark KJ, Dsouza NR, Zimmermann MT, Litzow M, Jacobi N, Klee EW, Smogorzewska A, and Patnaik MM
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- Fanconi Anemia Complementation Group Proteins, Humans, Phenotype, Ubiquitin-Conjugating Enzymes, Fanconi Anemia diagnosis, Fanconi Anemia genetics
- Published
- 2021
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8. Impact of integrated translational research on clinical exome sequencing.
- Author
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Klee EW, Cousin MA, Pinto E Vairo F, Morales-Rosado JA, Macke EL, Jenkinson WG, Ferrer A, Schultz-Rogers LE, Olson RJ, Oliver GR, Sigafoos AN, Schwab TL, Zimmermann MT, Urrutia RA, Kaiwar C, Gupta A, Blackburn PR, Boczek NJ, Prochnow CA, Lowy RJ, Mulvihill LA, McAllister TM, Aoudia SL, Kruisselbrink TM, Gunderson LB, Kemppainen JL, Fisher LJ, Tarnowski JM, Hager MM, Kroc SA, Bertsch NL, Agre KE, Jackson JL, Macklin-Mantia SK, Murphree MI, Rust LM, Summer Bolster JM, Beck SA, Atwal PS, Ellingson MS, Barnett SS, Rasmussen KJ, Lahner CA, Niu Z, Hasadsri L, Ferber MJ, Marcou CA, Clark KJ, Pichurin PN, Deyle DR, Morava-Kozicz E, Gavrilova RH, Dhamija R, Wierenga KJ, Lanpher BC, Babovic-Vuksanovic D, Farrugia G, Schimmenti LA, Stewart AK, and Lazaridis KN
- Subjects
- Genetic Testing, Humans, Phenotype, Translational Research, Biomedical, Exome Sequencing, Exome genetics, Undiagnosed Diseases
- Abstract
Purpose: Exome sequencing often identifies pathogenic genetic variants in patients with undiagnosed diseases. Nevertheless, frequent findings of variants of uncertain significance necessitate additional efforts to establish causality before reaching a conclusive diagnosis. To provide comprehensive genomic testing to patients with undiagnosed disease, we established an Individualized Medicine Clinic, which offered clinical exome testing and included a Translational Omics Program (TOP) that provided variant curation, research activities, or research exome sequencing., Methods: From 2012 to 2018, 1101 unselected patients with undiagnosed diseases received exome testing. Outcomes were reviewed to assess impact of the TOP and patient characteristics on diagnostic rates through descriptive and multivariate analyses., Results: The overall diagnostic yield was 24.9% (274 of 1101 patients), with 174 (15.8% of 1101) diagnosed on the basis of clinical exome sequencing alone. Four hundred twenty-three patients with nondiagnostic or without access to clinical exome sequencing were evaluated by the TOP, with 100 (9% of 1101) patients receiving a diagnosis, accounting for 36.5% of the diagnostic yield. The identification of a genetic diagnosis was influenced by the age at time of testing and the disease phenotype of the patient., Conclusion: Integration of translational research activities into clinical practice of a tertiary medical center can significantly increase the diagnostic yield of patients with undiagnosed disease.
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- 2021
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9. Characterization of Gene Repression by Designed Transcription Activator-like Effector Dimer Proteins.
- Author
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Becker NA, Peters JP, Schwab TL, Phillips WJ, Wallace JP, Clark KJ, and Maher LJ 3rd
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- DNA, Bacterial, Escherichia coli genetics, Escherichia coli metabolism, Gene Expression Regulation, Bacterial, Lac Operon genetics, Lac Repressors genetics, Lac Repressors metabolism, Nucleic Acid Conformation, Escherichia coli Proteins genetics, Escherichia coli Proteins metabolism, Transcription Activator-Like Effectors
- Abstract
Gene regulation by control of transcription initiation is a fundamental property of living cells. Much of our understanding of gene repression originated from studies of the Escherichia coli lac operon switch, in which DNA looping plays an essential role. To validate and generalize principles from lac for practical applications, we previously described artificial DNA looping driven by designed transcription activator-like effector dimer (TALED) proteins. Because TALE monomers bind the idealized symmetrical lac operator sequence in two orientations, our prior studies detected repression due to multiple DNA loops. We now quantitatively characterize gene repression in living E. coli by a collection of individual TALED loops with systematic loop length variation. Fitting of a thermodynamic model allows unequivocal demonstration of looping and comparison of the engineered TALED repression system with the natural lac repressor system., (Copyright © 2020 Biophysical Society. Published by Elsevier Inc. All rights reserved.)
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- 2020
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10. Haploinsufficiency as a disease mechanism in GNB1-associated neurodevelopmental disorder.
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Schultz-Rogers L, Masuho I, Pinto E Vairo F, Schmitz CT, Schwab TL, Clark KJ, Gunderson L, Pichurin PN, Wierenga K, Martemyanov KA, and Klee EW
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- Child, Child, Preschool, Developmental Disabilities pathology, Female, GTP-Binding Protein beta Subunits metabolism, HEK293 Cells, Humans, Intellectual Disability pathology, Male, Mutation, Missense, RNA Splicing, Seizures pathology, Signal Transduction, Developmental Disabilities genetics, GTP-Binding Protein beta Subunits genetics, Haploinsufficiency, Intellectual Disability genetics, Loss of Function Mutation, Seizures genetics
- Abstract
Background: GNB1 encodes a subunit of a heterotrimeric G-protein complex that transduces intracellular signaling cascades. Disruptions to the gene have previously been shown to be embryonic lethal in knockout mice and to cause complex neurodevelopmental disorders in humans. To date, the majority of variants associated with disease in humans have been missense variants in exons 5-7., Methods: Genetic sequencing was performed on two patients presenting with complex neurological phenotypes including intellectual disability, hypotonia, and in one patient seizures. Reported variants were assessed using RNA sequencing and functional BRET/BiFC assays., Results: A splice variant reported in patient 1 was confirmed to cause usage of a cryptic splice site leading to a truncated protein product. Patient 2 was reported to have a truncating variant. BRET and BiFC assays of both patient variants confirmed both were deficient in inducing GPCR-induced G protein activation due to lack of dimer formation with the Gγ subunit., Conclusion: Here, we report two patients with functionally confirmed loss of function variants in GNB1 and neurodevelopmental phenotypes including intellectual disability, hypotonia, and seizures in one patient. These results suggest haploinsufficiency of GNB1 is a mechanism for neurodevelopmental disorders in humans., (© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)
- Published
- 2020
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11. A tailored approach to fusion transcript identification increases diagnosis of rare inherited disease.
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Oliver GR, Tang X, Schultz-Rogers LE, Vidal-Folch N, Jenkinson WG, Schwab TL, Gaonkar K, Cousin MA, Nair A, Basu S, Chanana P, Oglesbee D, and Klee EW
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- Adolescent, Adult, Aged, Child, Child, Preschool, Female, Genetic Markers, Humans, Infant, Inheritance Patterns, Male, Middle Aged, Phenotype, Workflow, Young Adult, Genetic Association Studies methods, Genetic Diseases, Inborn diagnosis, Genetic Diseases, Inborn genetics, Genetic Predisposition to Disease, Mutant Chimeric Proteins genetics, Rare Diseases diagnosis, Rare Diseases genetics
- Abstract
Background: RNA sequencing has been proposed as a means of increasing diagnostic rates in studies of undiagnosed rare inherited disease. Recent studies have reported diagnostic improvements in the range of 7.5-35% by profiling splicing, gene expression quantification and allele specific expression. To-date however, no study has systematically assessed the presence of gene-fusion transcripts in cases of germline disease. Fusion transcripts are routinely identified in cancer studies and are increasingly recognized as having diagnostic, prognostic or therapeutic relevance. Isolated reports exist of fusion transcripts being detected in cases of developmental and neurological phenotypes, and thus, systematic application of fusion detection to germline conditions may further increase diagnostic rates. However, current fusion detection methods are unsuited to the investigation of germline disease due to performance biases arising from their development using tumor, cell-line or in-silico data., Methods: We describe a tailored approach to fusion candidate identification and prioritization in a cohort of 47 undiagnosed, suspected inherited disease patients. We modify an existing fusion transcript detection algorithm by eliminating its cell line-derived filtering steps, and instead, prioritize candidates using a custom workflow that integrates genomic and transcriptomic sequence alignment, biological and technical annotations, customized categorization logic, and phenotypic prioritization., Results: We demonstrate that our approach to fusion transcript identification and prioritization detects genuine fusion events excluded by standard analyses and efficiently removes phenotypically unimportant candidates and false positive events, resulting in a reduced candidate list enriched for events with potential phenotypic relevance. We describe the successful genetic resolution of two previously undiagnosed disease cases through the detection of pathogenic fusion transcripts. Furthermore, we report the experimental validation of five additional cases of fusion transcripts with potential phenotypic relevance., Conclusions: The approach we describe can be implemented to enable the detection of phenotypically relevant fusion transcripts in studies of rare inherited disease. Fusion transcript detection has the potential to increase diagnostic rates in rare inherited disease and should be included in RNA-based analytical pipelines aimed at genetic diagnosis., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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12. RINT1 Bi-allelic Variations Cause Infantile-Onset Recurrent Acute Liver Failure and Skeletal Abnormalities.
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Cousin MA, Conboy E, Wang JS, Lenz D, Schwab TL, Williams M, Abraham RS, Barnett S, El-Youssef M, Graham RP, Gutierrez Sanchez LH, Hasadsri L, Hoffmann GF, Hull NC, Kopajtich R, Kovacs-Nagy R, Li JQ, Marx-Berger D, McLin V, McNiven MA, Mounajjed T, Prokisch H, Rymen D, Schulze RJ, Staufner C, Yang Y, Clark KJ, Lanpher BC, and Klee EW
- Subjects
- Age of Onset, Alleles, Amino Acid Sequence, Bone Diseases, Developmental metabolism, Bone Diseases, Developmental pathology, Cell Cycle Proteins metabolism, Child, Child, Preschool, Female, Fibroblasts metabolism, Golgi Apparatus metabolism, Golgi Apparatus pathology, Humans, Infant, Liver Failure, Acute metabolism, Liver Failure, Acute pathology, Male, Pedigree, Protein Transport, Recurrence, Sequence Homology, Autophagy, Bone Diseases, Developmental etiology, Cell Cycle Proteins genetics, Fibroblasts pathology, Liver Failure, Acute etiology, Mutation
- Abstract
Pediatric acute liver failure (ALF) is life threatening with genetic, immunologic, and environmental etiologies. Approximately half of all cases remain unexplained. Recurrent ALF (RALF) in infants describes repeated episodes of severe liver injury with recovery of hepatic function between crises. We describe bi-allelic RINT1 alterations as the cause of a multisystem disorder including RALF and skeletal abnormalities. Three unrelated individuals with RALF onset ≤3 years of age have splice alterations at the same position (c.1333+1G>A or G>T) in trans with a missense (p.Ala368Thr or p.Leu370Pro) or in-frame deletion (p.Val618_Lys619del) in RINT1. ALF episodes are concomitant with fever/infection and not all individuals have complete normalization of liver function testing between episodes. Liver biopsies revealed nonspecific liver damage including fibrosis, steatosis, or mild increases in Kupffer cells. Skeletal imaging revealed abnormalities affecting the vertebrae and pelvis. Dermal fibroblasts showed splice-variant mediated skipping of exon 9 leading to an out-of-frame product and nonsense-mediated transcript decay. Fibroblasts also revealed decreased RINT1 protein, abnormal Golgi morphology, and impaired autophagic flux compared to control. RINT1 interacts with NBAS, recently implicated in RALF, and UVRAG, to facilitate Golgi-to-ER retrograde vesicle transport. During nutrient depletion or infection, Golgi-to-ER transport is suppressed and autophagy is promoted through UVRAG regulation by mTOR. Aberrant autophagy has been associated with the development of similar skeletal abnormalities and also with liver disease, suggesting that disruption of these RINT1 functions may explain the liver and skeletal findings. Clarifying the pathomechanism underlying this gene-disease relationship may inform therapeutic opportunities., (Copyright © 2019 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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13. Novel zebrafish behavioral assay to identify modifiers of the rapid, nongenomic stress response.
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Lee HB, Schwab TL, Sigafoos AN, Gauerke JL, Krug RG 2nd, Serres MR, Jacobs DC, Cotter RP, Das B, Petersen MO, Daby CL, Urban RM, Berry BC, and Clark KJ
- Subjects
- Animals, Hypothalamo-Hypophyseal System metabolism, Mutation, Pituitary-Adrenal System metabolism, Receptors, Corticotropin genetics, Receptors, Glucocorticoid genetics, Receptors, Mineralocorticoid genetics, Zebrafish genetics, Zebrafish Proteins genetics, Behavior, Animal, Locomotion, Stress, Physiological, Zebrafish physiology
- Abstract
When vertebrates face acute stressors, their bodies rapidly undergo a repertoire of physiological and behavioral adaptations, which is termed the stress response. Rapid changes in heart rate and blood glucose levels occur via the interaction of glucocorticoids and their cognate receptors following hypothalamic-pituitary-adrenal axis activation. These physiological changes are observed within minutes of encountering a stressor and the rapid time domain rules out genomic responses that require gene expression changes. Although behavioral changes corresponding to physiological changes are commonly observed, it is not clearly understood to what extent hypothalamic-pituitary-adrenal axis activation dictates adaptive behavior. We hypothesized that rapid locomotor response to acute stressors in zebrafish requires hypothalamic-pituitary-interrenal (HPI) axis activation. In teleost fish, interrenal cells are functionally homologous to the adrenocortical layer. We derived eight frameshift mutants in genes involved in HPI axis function: two mutants in exon 2 of mc2r (adrenocorticotropic hormone receptor), five in exon 2 or 5 of nr3c1 (glucocorticoid receptor [GR]) and two in exon 2 of nr3c2 (mineralocorticoid receptor [MR]). Exposing larval zebrafish to mild environmental stressors, acute changes in salinity or light illumination, results in a rapid locomotor response. We show that this locomotor response requires a functioning HPI axis via the action of mc2r and the canonical GR encoded by nr3c1 gene, but not MR (nr3c2). Our rapid behavioral assay paradigm based on HPI axis biology can be used to screen for genetic and environmental modifiers of the hypothalamic-pituitary-adrenal axis and to investigate the effects of corticosteroids and their cognate receptor interactions on behavior., (© 2018 The Authors. Genes, Brain and Behavior published by International Behavioural and Neural Genetics Society and John Wiley & Sons Ltd.)
- Published
- 2019
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14. Bacterial gene control by DNA looping using engineered dimeric transcription activator like effector (TALE) proteins.
- Author
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Becker NA, Schwab TL, Clark KJ, and Maher LJ 3rd
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- DNA chemistry, Escherichia coli Proteins metabolism, Lac Operon, Lac Repressors metabolism, Models, Genetic, Protein Engineering, Protein Multimerization, Transcription Activator-Like Effectors chemistry, Transcription Activator-Like Effectors metabolism, Gene Expression Regulation, Bacterial, Transcription Activator-Like Effectors genetics
- Abstract
Genetic switches must alternate between states whose probabilities are dependent on regulatory signals. Classical examples of transcriptional control in bacteria depend on repressive DNA loops anchored by proteins whose structures are sensitive to small molecule inducers or co-repressors. We are interested in exploiting these natural principles to engineer artificial switches for transcriptional control of bacterial genes. Here, we implement designed homodimeric DNA looping proteins ('Transcription Activator-Like Effector Dimers'; TALEDs) for this purpose in living bacteria. Using well-studied FKBP dimerization domains, we build switches that mimic regulatory characteristics of classical Escherichia coli lactose, galactose and tryptophan operon promoters, including induction or co-repression by small molecules. Engineered DNA looping using TALEDs is thus a new approach to tuning gene expression in bacteria. Similar principles may also be applicable for gene control in eukaryotes.
- Published
- 2018
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15. Allele-Specific Quantitative PCR for Accurate, Rapid, and Cost-Effective Genotyping.
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Lee HB, Schwab TL, Koleilat A, Ata H, Daby CL, Cervera RL, McNulty MS, Bostwick HS, and Clark KJ
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- Alleles, Animals, Cost-Benefit Analysis, DNA Primers, Genotype, Sequence Analysis, DNA, Polymerase Chain Reaction economics, Polymerase Chain Reaction methods, Zebrafish genetics, Zebrafish Proteins genetics
- Abstract
Customizable endonucleases such as transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) enable rapid generation of mutant strains at genomic loci of interest in animal models and cell lines. With the accelerated pace of generating mutant alleles, genotyping has become a rate-limiting step to understanding the effects of genetic perturbation. Unless mutated alleles result in distinct morphological phenotypes, mutant strains need to be genotyped using standard methods in molecular biology. Classic restriction fragment length polymorphism (RFLP) or sequencing is labor-intensive and expensive. Although simpler than RFLP, current versions of allele-specific PCR may still require post-polymerase chain reaction (PCR) handling such as sequencing, or they are more expensive if allele-specific fluorescent probes are used. Commercial genotyping solutions can take weeks from assay design to result, and are often more expensive than assembling reactions in-house. Key components of commercial assay systems are often proprietary, which limits further customization. Therefore, we developed a one-step open-source genotyping method based on quantitative PCR. The allele-specific qPCR (ASQ) does not require post-PCR processing and can genotype germline mutants through either threshold cycle (Ct) or end-point fluorescence reading. ASQ utilizes allele-specific primers, a locus-specific reverse primer, universal fluorescent probes and quenchers, and hot start DNA polymerase. Individual laboratories can further optimize this open-source system as we completely disclose the sequences, reagents, and thermal cycling protocol. We have tested the ASQ protocol to genotype alleles in five different genes. ASQ showed a 98-100% concordance in genotype scoring with RFLP or Sanger sequencing outcomes. ASQ is time-saving because a single qPCR without post-PCR handling suffices to score genotypes. ASQ is cost-effective because universal fluorescent probes negate the necessity of designing expensive probes for each locus.
- Published
- 2016
- Full Text
- View/download PDF
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