Publications by authors named "Shawn Westaway"

24 Publications

  • Page 1 of 1

The effects of noncoding aquaporin-4 single-nucleotide polymorphisms on cognition and functional progression of Alzheimer's disease.

Alzheimers Dement (N Y) 2017 Sep 26;3(3):348-359. Epub 2017 May 26.

Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.

Introduction: The glymphatic system is a brain-wide perivascular network that facilitates clearance of proteins, including amyloid β, from the brain interstitium through the perivascular exchange of cerebrospinal fluid and interstitial fluid. The astrocytic water channel aquaporin-4 (AQP4) is required for glymphatic system function, and impairment of glymphatic function in the aging brain is associated with altered AQP4 expression and localization. In human cortical tissue, alterations in AQP4 expression and localization are associated with Alzheimer's disease (AD) status and pathology. Although this suggests a potential role for AQP4 in the development or progression of AD, the relationship between of naturally occurring variants in the human gene and cognitive function has not yet been evaluated.

Methods: Using data from several longitudinal aging cohorts, we investigated the association between five single-nucleotide polymorphisms (SNPs) and the rate of cognitive decline in participants with a diagnosis of AD.

Results: None of the five SNPs were associated with different rates of AD diagnosis, age of dementia onset in trial subjects. No association between SNPs with histological measures of AD pathology, including Braak stage or neuritic plaque density was observed. However, SNPs were associated with altered rates of cognitive decline after AD diagnosis, with two SNPS (rs9951307 and rs3875089) associated with slower cognitive decline and two (rs3763040 and rs3763043) associated with more rapid cognitive decline after AD diagnosis.

Discussion: These results provide the first evidence that variations in the gene, whose gene product AQP4 is vital for glymphatic pathway function, may modulate the progression of cognitive decline in AD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.trci.2017.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5651426PMC
September 2017

Cyanide and the human brain: perspectives from a model of food (cassava) poisoning.

Ann N Y Acad Sci 2016 08 23;1378(1):50-57. Epub 2016 Jul 23.

National Nutrition Program, Ministry of Health, and Kinshasa School of Public Health, Kinshasa, Congo.

Threats by fundamentalist leaders to use chemical weapons have resulted in renewed interest in cyanide toxicity. Relevant insights may be gained from studies on cyanide mass intoxication in populations relying on cyanogenic cassava as the main source of food. In these populations, sublethal concentrations (up to 80 μmol/l) of cyanide in the blood are commonplace and lead to signs of acute toxicity. Long-term toxicity signs include a distinct and irreversible spastic paralysis, known as konzo, and cognition deficits, mainly in sequential processing (visual-spatial analysis) domains. Toxic culprits include cyanide (mitochondrial toxicant), thiocyanate (AMPA-receptor chaotropic cyanide metabolite), cyanate (protein-carbamoylating cyanide metabolite), and 2-iminothiazolidine-4-carboxylic acid (seizure inducer). Factors of susceptibility include younger age, female gender, protein-deficient diet, and, possibly, the gut functional metagenome. The existence of uniquely exposed and neurologically affected populations offers invaluable research opportunities to develop a comprehensive understanding of cyanide toxicity and test or validate point-of-care diagnostic tools and treatment options to be included in preparedness kits in response to cyanide-related threats.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5063682PMC
http://dx.doi.org/10.1111/nyas.13159DOI Listing
August 2016

Common variants in CASQ2, GPD1L, and NOS1AP are significantly associated with risk of sudden death in patients with coronary artery disease.

Circ Cardiovasc Genet 2011 Aug 17;4(4):397-402. Epub 2011 Jun 17.

The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.

Background: Recent evidence suggests a genetic component for sudden cardiac death (SCD) in subjects with coronary artery disease (CAD). We conducted a systematic candidate-gene approach using haplotype-tagging single nucleotide polymorphisms (htSNPs) to identify genes associated with SCD risk in the context of CAD.

Methods And Results: We investigated 1424 htSNPs representing 18 genes with mutations described in patients with ventricular arrhythmias in 291 subjects from the Oregon Sudden Unexpected Death Study (Ore-SUDS). The Ore-SUDS is an ongoing prospective investigation of SCD in the Portland, OR, metropolitan area (population, 1 000 000). SCD cases were ascertained from multiple sources and medical records were reviewed to determine the presence of CAD. A total of 36 SNPs were associated with risk of SCD (uncorrected probability values <0.01) in the initial study sample. These SNPs were subsequently tested for replication in an independent case-control study sample from the Ore-SUDS (n=688). The association analysis in the replication stage revealed 6 SNPs associated with SCD: CASQ2 region (rs17500488, P=0.04; rs3010396, P=0.007; rs7366407; P=0.04), NOS1AP (rs12084280, P=0.04; rs10918859, P=0.02), and 1 SNP located ≈26 kb upstream of GPD1L (rs9862154, P=0.04).

Conclusions: Common variations in or near CASQ2, GPD1L, and NOS1AP are associated with increased risk of SCD in patients with CAD. These findings provide further evidence for overlap between the genetic architecture of rare and common forms of SCD, and replication in additional populations is warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3160237PMC
http://dx.doi.org/10.1161/CIRCGENETICS.111.959916DOI Listing
August 2011

Microcephaly genes and risk of late-onset Alzheimer disease.

Alzheimer Dis Assoc Disord 2011 Jul-Sep;25(3):276-82

Portland Veterans Affairs Medical Center, Oregon Health and Science University, Portland, OR.

Brain development in the early stages of life has been suggested to be one of the factors that may influence an individual's risk of Alzheimer disease (AD) later in life. Four microcephaly genes, which regulate brain development in utero and have been suggested to play a role in the evolution of the human brain, were selected as candidate genes that may modulate the risk of AD. We examined the association between single nucleotide polymorphisms tagging common sequence variations in these genes and risk of AD in two case-control samples. We found that the G allele of rs2442607 in microcephalin 1 was associated with an increased risk of AD (under an additive genetic model, P=0.01; odds ratio=3.41; confidence interval, 1.77-6.57). However, this association was not replicated using another case-control sample research participants from the Alzheimer Disease Neuroimaging Initiative. We conclude that the common variations we measured in the 4 microcephaly genes do not affect the risk of AD or that their effect size is small.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/WAD.0b013e31820a1d32DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136560PMC
December 2011

Discordant expression of miR-103/7 and pantothenate kinase host genes in mouse.

Mol Genet Metab 2010 Oct-Nov;101(2-3):292-5. Epub 2010 Aug 4.

Molecular and Medical Genetics, Oregon Health & Science University, Portland OR, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA.

miR-103 and miR-107, microRNAs hosted by pantothenate kinase genes, are proposed to regulate cellular lipid metabolism. microRNA-mediated regulation is complex, potentially affecting expression of the host gene, related enzymes within the same pathway, or apparently distinct targets. Using qRT-PCR, we demonstrate that miR-103 and miR-107 expression does not correlate with expression of host pantothenate kinase genes in mouse tissues. The miR-103/7 family thus provides an intriguing model for dissecting microRNA transcription, processing and coordinated function within host genes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ymgme.2010.07.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951883PMC
January 2011

Alzheimer disease pathology in cognitively healthy elderly: a genome-wide study.

Neurobiol Aging 2011 Dec 7;32(12):2113-22. Epub 2010 May 7.

Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA.

Many elderly individuals remain dementia-free throughout their life. However, some of these individuals exhibit Alzheimer disease neuropathology on autopsy, evidenced by neurofibrillary tangles (NFTs) in AD-specific brain regions. We conducted a genome-wide association study to identify genetic mechanisms that distinguish non-demented elderly with a heavy NFT burden from those with a low NFT burden. The study included 299 non-demented subjects with autopsy (185 subjects with low and 114 with high NFT levels). Both a genotype test, using logistic regression, and an allele test provided consistent evidence that variants in the RELN gene are associated with neuropathology in the context of cognitive health. Immunohistochemical data for reelin expression in AD-related brain regions added support for these findings. Reelin signaling pathways modulate phosphorylation of tau, the major component of NFTs, either directly or through β-amyloid pathways that influence tau phosphorylation. Our findings suggest that up-regulation of reelin may be a compensatory response to tau-related or beta-amyloid stress associated with AD even prior to the onset of dementia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neurobiolaging.2010.01.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990809PMC
December 2011

Reconstructability analysis as a tool for identifying gene-gene interactions in studies of human diseases.

Stat Appl Genet Mol Biol 2010 3;9:Article18. Epub 2010 Mar 3.

Eastern Washington University, USA.

There are a number of common human diseases for which the genetic component may include an epistatic interaction of multiple genes. Detecting these interactions with standard statistical tools is difficult because there may be an interaction effect, but minimal or no main effect. Reconstructability analysis (RA) uses Shannon's information theory to detect relationships between variables in categorical datasets. We applied RA to simulated data for five different models of gene-gene interaction, and find that even with heritability levels as low as 0.008, and with the inclusion of 50 non-associated genes in the dataset, we can identify the interacting gene pairs with an accuracy of > or =80%. We applied RA to a real dataset of type 2 non-insulin-dependent diabetes (NIDDM) cases and controls, and closely approximated the results of more conventional single SNP disease association studies. In addition, we replicated prior evidence for epistatic interactions between SNPs on chromosomes 2 and 15.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2202/1544-6115.1516DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861311PMC
June 2010

Infantile neuroaxonal dystrophy: what's most important for the diagnosis?

Eur J Paediatr Neurol 2008 Nov 21;12(6):491-500. Epub 2008 Mar 21.

Department of Child Neurology, Hospital de Crianças Maria Pia, Rua da Boavista, 827, 4050-111 Porto, Portugal.

Background And Aims: Infantile neuroaxonal dystrophy is a rare neurodegenerative disorder, with onset in the first 2 years of life. Mutations in the PLA2G6 gene were identified in patients with infantile neuroaxonal dystrophy. Our purpose was to review clinical, neurophysiologic, neuroradiologic and neuropathological features of our patients in order to identify the earliest signs of disease. We also correlate these data with the genotype in the mutation positive patients.

Methods: We reviewed the clinical reports, neurophysiologic and neuropathological studies and brain imaging of our patients. In five patients molecular analysis of the PLA2G6 gene was performed.

Results: We report 10 patients with infantile neuroaxonal dystrophy. Earliest symptoms presented between 6 and 18 months of age. The first manifestations were arrest in the acquisition of milestones or regression. The first neurological signs were generalized hypotonia and pyramidal signs. Fast rhythms on EEG were observed in all patients. Brain imaging studies showed cerebellar atrophy in all patients, with signal hyperintensity in the cerebellar cortex on T2-weighted images in five. All cases had characteristic axonal spheroids on skin biopsy. Mutations in the PLA2G6 gene were identified in the five patients studied. Three of them had the same homozygous mutations 2370T> G, Y790X.

Conclusions: Though mutations were detected in the patients studied, a clear genotype-phenotype correlation could not be ascertained. In the appropriate clinical context, characteristic brain imaging and fast rhythms on EEG can support the decision to perform molecular analysis and avoid skin biopsy to confirm diagnosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejpn.2008.01.005DOI Listing
November 2008

Gene symbol: PANK2. Disease: pantothenate kinase-associated neurodegeneration (PKAN).

Hum Genet 2006 Jul;119(6):679

Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland 97239, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Gene symbol: PANK2. Disease: pantothenate kinase-associated neurodegeneration (PKAN).

Hum Genet 2006 Jul;119(6):679

Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland 97239, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Gene symbol: PANK2. Disease: pantothenate kinase-associated neurodegeneration (PKAN).

Hum Genet 2006 Jul;119(6):678

Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland 97239, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Gene symbol: PANK2. Disease: pantothenate kinase-associated neurodegeneration (PKAN).

Hum Genet 2006 Jul;119(6):677

Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland 97239, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Gene symbol: PANK2. Disease: pantothenate kinase-associated neurodegeneration (PKAN).

Hum Genet 2006 Jul;119(6):673

Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland 97239, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Gene symbol: PANK2. Disease: pantothenate kinase-associated neurodegeneration (PKAN).

Hum Genet 2006 Jul;119(6):672

Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland 97239, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Gene symbol: PANK2. Disease: pantothenate kinase-associated neurodegeneration (PKAN).

Hum Genet 2006 Jul;119(6):671-2

Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland 97239, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Pantothenate kinase 2 mutation without 'eye-of-the-tiger' sign.

Pediatr Radiol 2006 Dec 5;36(12):1329; author reply 1330. Epub 2006 Oct 5.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00247-006-0309-9DOI Listing
December 2006

PLA2G6, encoding a phospholipase A2, is mutated in neurodegenerative disorders with high brain iron.

Nat Genet 2006 Jul 18;38(7):752-4. Epub 2006 Jun 18.

Section of Medical & Molecular Genetics, University of Birmingham School of Medicine, Edgbaston, Birmingham B15 2TT, UK.

Neurodegenerative disorders with high brain iron include Parkinson disease, Alzheimer disease and several childhood genetic disorders categorized as neuroaxonal dystrophies. We mapped a locus for infantile neuroaxonal dystrophy (INAD) and neurodegeneration with brain iron accumulation (NBIA) to chromosome 22q12-q13 and identified mutations in PLA2G6, encoding a calcium-independent group VI phospholipase A2, in NBIA, INAD and the related Karak syndrome. This discovery implicates phospholipases in the pathogenesis of neurodegenerative disorders with iron dyshomeostasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ng1826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2117328PMC
July 2006

Neuro-ophthalmologic and electroretinographic findings in pantothenate kinase-associated neurodegeneration (formerly Hallervorden-Spatz syndrome).

Am J Ophthalmol 2005 Aug;140(2):267-74

Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland 97201, USA.

Purpose: The onset of pantothenate kinase-associated neurodegeneration (PKAN) occurs in the first and second decade of life and a pigmentary retinal degeneration is a feature of the disorder. Since the neuro-ophthalmologic and electroretinographic (ERG) features have never been well delineated, we describe them in 16 patients with PKAN.

Design: Observational case series.

Methods: Sixteen patients with genetic and neuroimaging-confirmed PKAN were examined. Ten underwent neuro-ophthalmologic examination and all had ERGs.

Results: Of the 10 who underwent neuro-ophthalmologic examination, all showed saccadic pursuits and eight showed hypometric or slowed vertical saccades. Seven of eight had inability to suppress the vestibulo-ocular reflex; two patients could not cooperate. Two had square wave jerks and four had poor convergence. Vertical optokinetic responses were abnormal in five, and two patients had blepharospasm. Eight patients had sectoral iris paralysis and partial loss of the pupillary ruff consistent with Adie's pupils in both eyes. Only four of 10 examined patients showed a pigmentary retinopathy, but 11 of 16 had abnormal ERGs ranging from mild cone abnormalities to severe rod-cone dysfunction. No patient had optic atrophy. The PANK2 mutations of all of the patients were heterogeneous.

Conclusions: Adie's-like pupils, abnormal vertical saccades, and saccadic pursuits were very common. These findings suggest that mid-brain degeneration occurs in PKAN more frequently than previously thought. ERG abnormalities were present in approximately 70% and no patient had optic atrophy. Although genotype-ocular phenotype correlations could not be established, allelic differences probably contributed to the variable clinical expression of retinopathy and other clinical characteristics in these patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajo.2005.03.024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2169522PMC
August 2005

Novel compound heterozygous mutations in the PANK2 gene in a Chinese patient with atypical pantothenate kinase-associated neurodegeneration.

Mov Disord 2005 Jul;20(7):819-21

Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.

We investigated the presence of mutations in the pantothenate kinase (PANK2) gene in a 27-year-old male Chinese patient with atypical pantothenate kinase-associated neurodegeneration (PKAN), formerly Hallervorden-Spatz syndrome. Automated DNA sequence analyses revealed compound heterozygous mutations in the exon 3 and 5. This patient had a 10-year history of PKAN characterized by a slight tremor of the right hand when writing at onset and a slow progressive rigidity of the neck and the right arm and resting tremor in upper extremities. Dysarthria, dysphagia, and dystonic-athetoid movements of the face and right fingers were marked. Magnetic resonance showed the typical "eye-of-the-tiger" sign.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mds.20408DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2105744PMC
July 2005

Deficiency of pantothenate kinase 2 (Pank2) in mice leads to retinal degeneration and azoospermia.

Hum Mol Genet 2005 Jan 3;14(1):49-57. Epub 2004 Nov 3.

Department of Medicine, University of California, San Francisco, CA 94143, USA.

Pantothenate kinase-associated neurodegeneration (PKAN, formerly known as Hallervorden-Spatz syndrome) is a rare but devastating neurodegenerative disorder, resulting from an inherited defect in coenzyme A biosynthesis. As pathology in the human condition is limited to the central nervous system, specifically the retina and globus pallidus, we have generated a mouse knock-out of the orthologous murine gene (Pank2) to enhance our understanding of the mechanisms of disease and to serve as a testing ground for therapies. Over time, the homozygous null mice manifest retinal degeneration, as evidenced by electroretinography, light microscopy and pupillometry response. Specifically, Pank2 mice show progressive photoreceptor decline, with significantly lower scotopic a- and b-wave amplitudes, decreased cell number and disruption of the outer segment and reduced pupillary constriction response when compared with those of wild-type littermates. Additionally, the homozygous male mutants are infertile due to azoospermia, a condition that was not appreciated in the human. Arrest occurs in spermiogenesis, with complete absence of elongated and mature spermatids. In contrast to the human, however, no changes were observed in the basal ganglia by MRI or by histological exam, nor were there signs of dystonia, even after following the mice for one year. Pank2 mice are 20% decreased in weight when compared with their wild-type littermates; however, dysphagia was not apparent. Immunohistochemistry shows staining consistent with localization of Pank2 to the mitochondria in both the retina and the spermatozoa.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddi005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2117329PMC
January 2005

Mitochondrial localization of human PANK2 and hypotheses of secondary iron accumulation in pantothenate kinase-associated neurodegeneration.

Ann N Y Acad Sci 2004 Mar;1012:282-98

Department of Molecular and Medical Genetics, School of Medicine, Oregon Health and Science University, Portland 97239, USA.

Mutations in the pantothenate kinase 2 gene (PANK2) lead to pantothenate kinase-associated neurodegeneration (PKAN, formerly Hallervorden-Spatz syndrome). This neurodegenerative disorder is characterized by iron accumulation in the basal ganglia. Pantothenate kinase is the first enzyme in the biosynthesis of coenzyme A from pantothenate (vitamin B(5)). PANK2, one of four human pantothenate kinase genes, is uniquely predicted to be targeted to mitochondria. We demonstrate mitochondrial localization of PANK2 and speculate on mechanisms of secondary iron accumulation in PKAN. Furthermore, PANK2 uses an unconventional translational start codon, CUG, which is polymorphic in the general population. The variant sequence, CAG (allele frequency: 0.05), leads to skipping of the mitochondrial targeting signal and cytosolic localization of PANK2. This common variant may cause mitochondrial dysfunction and impart susceptibility to late-onset neurodegenerative disorders with brain iron accumulation, including Parkinson's disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1196/annals.1306.023DOI Listing
March 2004

Genetic, clinical, and radiographic delineation of Hallervorden-Spatz syndrome.

N Engl J Med 2003 Jan;348(1):33-40

Department of Molecular and Medical Genetics, School of Medicine, Oregon Health and Science University, Portland, OR 97201-3098, USA.

Background: Hallervorden-Spatz syndrome is an autosomal recessive disorder characterized by dystonia, parkinsonism, and iron accumulation in the brain. Many patients with this disease have mutations in the gene encoding pantothenate kinase 2 (PANK2); these patients are said to have pantothenate kinase-associated neurodegeneration. In this study, we compared the clinical and radiographic features of patients with Hallervorden-Spatz syndrome with and without mutations in PANK2.

Methods: One hundred twenty-three patients from 98 families with a diagnosis of Hallervorden-Spatz syndrome were classified on the basis of clinical assessment as having classic disease (characterized by early onset with rapid progression) or atypical disease (later onset with slow progression). Their genomic DNA was sequenced for PANK2 mutations.

Results: All patients with classic Hallervorden-Spatz syndrome and one third of those with atypical disease had PANK2 mutations. Whereas almost all mutations in patients with atypical disease led to amino acid changes, those in patients with classic disease more often resulted in predicted protein truncation. Patients with atypical disease who had PANK2 mutations were more likely to have prominent speech-related and psychiatric symptoms than patients with classic disease or mutation-negative patients with atypical disease. In all patients with pantothenate kinase-associated neurodegeneration, whether classic or atypical, T2-weighted magnetic resonance imaging (MRI) of the brain showed a specific pattern of hyperintensity within the hypointense medial globus pallidus. This pattern was not seen in any patients without mutations.

Conclusions: PANK2 mutations are associated with all cases of classic Hallervorden-Spatz syndrome and one third of cases of atypical disease. A specific MRI pattern distinguishes patients with PANK2 mutations. Predicted levels of pantothenate kinase 2 protein correlate with the severity of disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMoa020817DOI Listing
January 2003

Enhanced expression and HIV-1 inhibition of chimeric tRNA(Lys3)-ribozymes under dual U6 snRNA and tRNA promoters.

Mol Ther 2002 Oct;6(4):481-9

Division of Molecular Biology, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA.

We previously demonstrated that chimeric tRNA(Lys3)-ribozymes targeting the primer binding site of HIV produced virions with reduced infectivity. To further enhance the anti-HIV efficiency of these ribozymes by increasing their level of transcription, we designed several tRNA(Lys3) promoter variants and compared their expression levels from the internal tRNA(Lys3) promoters and also from an exogenous human U6 snRNA promoter. The dual U6/tRNA promoter constructs gave rise to much higher levels of expression than constructs that used only an internal tRNA promoter. The most abundant expression is produced when a U6 promoter drives a chimeric tRNA(Lys3)-ribozyme containing a mutation in the tRNA B box. As detected by fluorescent in situ hybridization, transcripts from a construct with the tRNA promoter alone localized strictly to the cytoplasm, whereas transcripts from dual U6/tRNA promoter were present in both the cytoplasm and the nucleus. Inhibition of HIV-1 correlates well with expression levels of the chimeric constructs. The results presented demonstrate that U6 and tRNA promoters can be placed in tandem for high-level expression of small RNA therapeutic transcripts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1006/mthe.2002.0696DOI Listing
October 2002
-->