Scott Q Harper

Nationwide Children's Hospital, Columbus, Ohio, United States

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Publications (39)248.37 Total impact

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    ABSTRACT: Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disorder with a 1 in 7500 incidence. Symptoms typically arise in young adulthood and most patients show clinical features before age 30. FSHD is characterized by progressive wasting and weakness of facial and shoulder-girdle muscles, although no consistent pattern of penetrance or severity exists. A hallmark characteristic of FSHD is asymmetrical muscle weakness. There are also non-muscular features including retinal vasculopathy and high frequency hearing loss. The current model of pathogenesis in FSHD involves mis-expression of the myotoxic DUX4 gene, but developing animal models has proven difficult. At previous meetings, we first described our transgenic reporter mice containing a putative DUX4 promoter cloned upstream of GFP. We generated three separate lines of DUX4 promoter-GFP mice to identify DUX4 expression patterns and the involvement of selected muscles in FSHD. In short, we found the DUX4 promoter directed GFP expression in the face and limbs of newborn and adult mice, as well as multiple cell types in the retina. Essentially all other organs were GFP negative with a few exceptions including the pancreas and brain. Closer analysis of GFP positive tissues has revealed extensive expression in both myogenic and neuronal cell types. Strikingly, all lines also showed variable penetrance and asymmetrical expression in all GFP-positive tissues, even within individual litters. We have recently created another transgenic line expressing a GFP-CRE fusion protein from the same DUX4 promoter. Importantly we see similar expression patterns to the original mice and are now using them to create an inducible DUX4 transgenic mouse. We have also created analogous AAV vectors to induce localized DUX4 expression at physiologically relevant levels. These models will aid in deciphering molecular mechanisms and developing therapeutic interventions for FSHD.
    Neuromuscular Disorders 10/2014; 24(s 9–10):797. · 3.46 Impact Factor
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    ABSTRACT: Recent progress suggests gene therapy may one day be an option for treating some forms of limb girdle muscular dystrophy (LGMD). Nevertheless, approaches targeting LGMD have so far focused on gene replacement strategies for recessive forms of the disease. In contrast, no attempts have been made to develop molecular therapies for any of the eight dominantly inherited forms of LGMD. Importantly, the emergence of RNA interference (RNAi) therapeutics in the last decade provided new tools to combat dominantly inherited LGMDs with molecular therapy. In this study, we describe the first RNAi-based, preclinical gene therapy approach for silencing a gene associated with dominant LGMD. To do this, we developed adeno-associated viral vectors (AAV6) carrying designed therapeutic microRNAs targeting mutant myotilin (MYOT), which is the underlying cause of LGMD type 1A (LGMD1A). Our best MYOT-targeted microRNA vector (called miMYOT) significantly reduced mutant myotilin mRNA and soluble protein expression in muscles of LGMD1A mice (the TgT57I model) both 3 and 9 months after delivery, demonstrating short- and long-term silencing effects. This MYOT gene silencing subsequently decreased deposition of MYOT-seeded intramuscular protein aggregates, which is the hallmark feature of LGMD1A. Histological improvements were accompanied by significant functional correction, as miMYOT-treated animals showed increased muscle weight and improved specific force in the gastrocnemius, which is one of the most severely affected muscles in TgT57I mice and patients with dominant myotilin mutations. These promising results in a preclinical model of LGMD1A support the further development of RNAi-based molecular therapy as a prospective treatment for LGMD1A. Furthermore, this study sets a foundation that may be refined and adapted to treat other dominant LGMD and related disorders.
    Molecular therapy. Nucleic acids. 04/2014; 3:e160.
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    ABSTRACT: Gene therapy has historically focused on delivering protein-coding genes to target cells or tissues using a variety of vectors. In recent years, the field has expanded to include gene-silencing strategies involving delivery of noncoding inhibitory RNAs, such as short hairpin RNAs or microRNAs (miRNAs). Often called RNA interference (RNAi) triggers, these small inhibitory RNAs are difficult or impossible to visualize in living cells or tissues. To circumvent this detection problem and ensure efficient delivery in preclinical studies, vectors can be engineered to coexpress a fluorescent reporter gene to serve as a marker of transduction. In this study, we set out to optimize adeno-associated viral (AAV) vectors capable of delivering engineered miRNAs and green fluorescent protein (GFP) reporter genes to skeletal muscle. Although the more broadly utilized enhanced GFP (eGFP) gene derived from the jellyfish, Aequorea victoria was a conventional choice, we were concerned about some previous studies suggesting this protein was myotoxic. We thus opted to test vectors carrying the humanized Renilla reniformis-derived GFP (hrGFP) gene, which has not seen as extensive usage as eGFP but was purported to be a safer and less cytotoxic alternative. Employing AAV6 vector dosages typically used in preclinical gene transfer studies (3×10(10) -1 × 10(11) particles), we found that hrGFP caused dose-dependent myopathy when delivered to wild-type (wt) mouse muscle, whereas identical titers of AAV6 carrying eGFP were relatively benign. Dose de-escalation at or below 8 × 10(9) AAV particles effectively reduced or eliminated hrGFP-associated myotoxicity, but also had dampening effects on green fluorescence and miRNA-mediated gene silencing in whole muscles. We conclude that hrGFP is impractical for use as a transduction marker in preclinical, AAV-based RNA interference therapy studies where adult mouse muscle is the target organ. Moreover, our data support that eGFP is superior to hrGFP as a reporter gene in mouse muscle. These results may impact the design of future preclinical gene therapy studies targeting muscles and non-muscle tissues alike.Molecular Therapy - Nucleic Acids (2013) 2, e86; doi:10.1038/mtna.2013.16; published online 16 April 2013.
    Molecular therapy. Nucleic acids. 01/2013; 2:e86.
  • Scott Q Harper
    Proceedings of the National Academy of Sciences 12/2012; · 9.81 Impact Factor
  • Jian Liu, Scott Q Harper
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    ABSTRACT: Limb Girdle Muscular Dystrophy (LGMD) refers to a group of 25 genetic diseases linked by common clinical features, including wasting of muscles supporting the pelvic and shoulder girdles. Cardiac involvement may also occur. Like other muscular dystrophies, LGMDs are currently incurable, but prospective gene replacement therapies targeting recessive forms have shown promise in pre-clinical and clinical studies. In contrast, little attention has been paid to developing gene therapy approaches for dominant forms of LGMD, which would likely benefit from disease gene silencing. Despite the lack of focus to date on developing gene therapies for dominant LGMDs, the field is not starting at square one, since translational studies on recessive LGMDs provided a framework that can be applied to treating dominant forms of the disease. In this manuscript, we discuss the prospects of treating dominantly inherited forms of LGMD with gene silencing approaches.
    Current Gene Therapy 08/2012; 12(4):307-14. · 5.32 Impact Factor
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    ABSTRACT: Paired-like homeodomain transcription factor 1 (PITX1) was specifically up-regulated in patients with facioscapulohumeral muscular dystrophy (FSHD) by comparing the genome-wide mRNA expression profiles of 12 neuromuscular disorders. In addition, it is the only known direct transcriptional target of the double homeobox protein 4 (DUX4) of which aberrant expression has been shown to be the cause of FSHD. To test the hypothesis that up-regulation of PITX1 contributes to the skeletal muscle atrophy seen in patients with FSHD, we generated a tet-repressible muscle-specific Pitx1 transgenic mouse model in which expression of PITX1 in skeletal muscle can be controlled by oral administration of doxycycline. After PITX1 was over-expressed in the skeletal muscle for 5 weeks, the mice exhibited significant loss of body weight and muscle mass, decreased muscle strength, and reduction of muscle fiber diameters. Among the muscles examined, the tibialis anterior, gastrocnemius, quadricep, bicep, tricep and deltoid showed significant reduction of muscle mass, while the soleus, masseter and diaphragm muscles were not affected. The most prominent pathological change was the development of atrophic muscle fibers with mild necrosis and inflammatory infiltration. The affected myofibers stained heavily with NADH-TR with the strongest staining in angular-shaped atrophic fibers. Some of the atrophic fibers were also positive for embryonic myosin heavy chain using immunohistochemistry. Immunoblotting showed that the p53 was up-regulated in the muscles over-expressing PITX1. The results suggest that the up-regulation of PITX1 followed by activation of p53-dependent pathways may play a major role in the muscle atrophy developed in the mouse model.
    Biology open. 07/2012; 1(7):629-639.
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    ABSTRACT: No treatment exists for facioscapulohumeral muscular dystrophy (FSHD), one of the most common inherited muscle diseases. Although FSHD can be debilitating, little effort has been made to develop targeted therapies. This lack of focus on targeted FSHD therapy perpetuated because the genes and pathways involved in the disorder were not understood. Now, more than 2 decades after efforts to decipher the root cause of FSHD began, this barrier to translation is finally lowering. Specifically, several recent studies support an FSHD pathogenesis model involving overexpression of the myopathic DUX4 gene. DUX4 inhibition has therefore emerged as a promising therapeutic strategy for FSHD. In this study, we tested a preclinical RNA interference (RNAi)-based DUX4 gene silencing approach as a prospective treatment for FSHD. We found that adeno-associated viral (AAV) vector-delivered therapeutic microRNAs corrected DUX4-associated myopathy in mouse muscle. These results provide proof-of-principle for RNAi therapy of FSHD through DUX4 inhibition.
    Molecular Therapy 04/2012; 20(7):1417-23. · 7.04 Impact Factor
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    ABSTRACT: RNA interference (RNAi) is a conserved gene silencing mechanism mediated by small inhibitory microRNAs (miRNAs).Promoter-driven miRNA expression vectors have emerged as important tools for delivering natural or artificially designed miRNAs to eukaryotic cells and organisms. Such systems can be used to query the normal or pathogenic functions of natural miRNAs or messenger RNAs, or to therapeutically silence disease genes. As with any molecular cloning procedure, building miRNA-based expression constructs requires a time investment and some molecular biology skills. To improve efficiency and accelerate the construction process, we developed a method to rapidly generate miRNA expression vectors using recombinases instead of more traditional cut-and-paste molecular cloning techniques. In addition to streamlining the construction process, our cloning strategy provides vectors with added versatility. In our system, miRNAs can be constitutively expressed from the U6 promoter, or inducibly expressed by Cre recombinase. We also engineered a built-in mechanism to destroy the vector with Flp recombinase, if desired. Finally, to further simplify the construction process, we developed a software package that automates the prediction and design of optimal miRNA sequences using our system. We designed and tested a modular system to rapidly clone miRNA expression cassettes. Our strategy reduces the hands-on time required to successfully generate effective constructs, and can be implemented in labs with minimal molecular cloning expertise. This versatile system provides options that permit constitutive or inducible miRNA expression, depending upon the needs of the end user. As such, it has utility for basic or translational applications.
    BMC Biotechnology 11/2011; 11:107. · 2.17 Impact Factor
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    ABSTRACT: Muscular dystrophies, and other diseases of muscle, arise from recessive and dominant gene mutations. Gene replacement strategies may be beneficial for the former, while gene silencing approaches may provide treatment for the latter. In the last two decades, muscle-directed gene therapies were primarily focused on treating recessive disorders. This disparity at least partly arose because feasible mechanisms to silence dominant disease genes lagged behind gene replacement strategies. With the discovery of RNA interference (RNAi) and its subsequent development as a promising new gene silencing tool, the landscape has changed. In this study, our objective was to demonstrate proof-of-principle for RNAi therapy of a dominant myopathy in vivo. We tested the potential of adeno-associated viral (AAV)-delivered therapeutic microRNAs, targeting the human Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1), to correct myopathic features in mice expressing toxic levels of human FRG1 (FRG1(-high) mice). We found that FRG1 gene silencing improved muscle mass, strength, and histopathological abnormalities associated with muscular dystrophy in FRG1(-high) mice, thereby demonstrating therapeutic promise for treatment of dominantly inherited myopathies using RNAi. This approach potentially applies to as many as 29 different gene mutations responsible for myopathies inherited as dominant disorders.
    Molecular Therapy 07/2011; 19(11):2048-54. · 7.04 Impact Factor
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    ABSTRACT: MicroRNAs (miRNAs) have emerged as important modulators of eukaryotic gene expression through a process called RNA interference (RNAi). Over the last several years, a large amount of work has focused on understanding how miRNAs are expressed and processed to a biologically functional form. This knowledge has enabled the development of RNAi as a molecular tool for investigating basic biological questions or as a therapeutic technique. Artificial miRNA shuttle vectors can be engineered to mimic natural miRNAs and subsequently used to suppress any gene of interest. Here, we describe a simple method to build and functionally validate artificial miRNA shuttles. Key wordsRNAi–MicroRNA–miRNA, siRNA–Inhibitory RNA–Gene silencing–Gene therapy
    05/2011: pages 19-37;
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    ABSTRACT: Facioscapulohumeral muscular dystrophy (FSHD) is associated with D4Z4 repeat contraction on human chromosome 4q35. This genetic lesion does not result in complete loss or mutation of any gene. Consequently, the pathogenic mechanisms underlying FSHD have been difficult to discern. In leading FSHD pathogenesis models, D4Z4 contractions are proposed to cause epigenetic changes, which ultimately increase expression of genes with myopathic potential. Although no gene has been conclusively linked to FSHD development, recent evidence supports a role for the D4Z4-encoded DUX4 gene in FSHD. In this study, our objective was to test the in vivo myopathic potential of DUX4. We delivered DUX4 to zebrafish and mouse muscle by transposon-mediated transgenesis and adeno-associated viral vectors, respectively. Overexpression of DUX4, which encodes a transcription factor, caused abnormalities associated with muscular dystrophy in zebrafish and mice. This toxicity required DNA binding, because a DUX4 DNA binding domain mutant produced no abnormalities. Importantly, we found the myopathic effects of DUX4 were p53 dependent, as p53 inhibition mitigated DUX4 toxicity in vitro, and muscles from p53 null mice were resistant to DUX4-induced damage. Our work demonstrates the myopathic potential of DUX4 in animal muscle. Considering previous studies showed DUX4 was elevated in FSHD patient muscles, our data support the hypothesis that DUX4 overexpression contributes to FSHD development. Moreover, we provide a p53-dependent mechanism for DUX4 toxicity that is consistent with previous studies showing p53 pathway activation in FSHD muscles. Our work justifies further investigation of DUX4 and the p53 pathway in FSHD pathogenesis.
    Annals of Neurology 03/2011; 69(3):540-52. · 11.19 Impact Factor
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    ABSTRACT: Protein phosphatase 2A (PP2A) is one of the most abundantly expressed serine/threonine protein phosphatases. A large body of evidence suggests that PP2A is a tumor suppressor and plays critical roles in regulating apoptosis. PP2A is a heterotrimeric protein complex. Its substrate specificity, localization, and activity are regulated by regulatory subunits of PP2A. A recent study has demonstrated that single nucleotide polymorphism in B56ε (PPP2R5E), a B56 family regulatory subunit of PP2A, is associated with human soft tissue sarcoma. This raises the possibility that B56ε is involved in tumorigenesis and plays important roles in regulating apoptosis. However, this hypothesis has not been tested experimentally. Our previous studies revealed that B56ε regulates a number of developmental signaling pathways during early embryonic patterning. Here we report novel functions of B56ε in regulating apoptosis. We provide evidence that B56ε has both anti- and pro-apoptotic functions. B56ε suppresses p53-independent apoptosis during neural development, but triggers p53-dependent apoptosis. Mechanistically, B56ε regulates the p53-dependent apoptotic pathway solely through controlling the stability of p53 protein. In addition to its function in regulating apoptosis, we show that B56ε undergoes proteolytic cleavage. The cleavage of B56ε is mediated by caspase-3 and occurs on the carboxyl side of an evolutionarily conserved N-terminal "DKXD" motif. These results demonstrate that B56ε, a substrate of caspase-3, is an essential regulator of apoptosis. So far, we have identified an alternative translation isoform and a caspase cleavage product of B56ε. The significance of post-transcriptional regulation of B56ε is discussed.
    Journal of Biological Chemistry 11/2010; 285(45):34493-502. · 4.65 Impact Factor
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    ABSTRACT: Protein phosphatase 2A (PP2A) is one of the most abundantly expressed serine/threonine protein phosphatases. A large body of evidence suggests that PP2A is a tumor suppressor and plays critical roles in regulating apoptosis. PP2A is a heterotrimeric protein complex. Its substrate specificity, localization, and activity are regulated by regulatory subunits of PP2A. A recent study has demonstrated that single nucleotide polymorphism in B56ϵ (PPP2R5E), a B56 family regulatory subunit of PP2A, is associated with human soft tissue sarcoma. This raises the possibility that B56ϵ is involved in tumorigenesis and plays important roles in regulating apoptosis. However, this hypothesis has not been tested experimentally. Our previous studies revealed that B56ϵ regulates a number of developmental signaling pathways during early embryonic patterning. Here we report novel functions of B56ϵ in regulating apoptosis. We provide evidence that B56ϵ has both anti- and pro-apoptotic functions. B56ϵ suppresses p53-independent apoptosis during neural development, but triggers p53-dependent apoptosis. Mechanistically, B56ϵ regulates the p53-dependent apoptotic pathway solely through controlling the stability of p53 protein. In addition to its function in regulating apoptosis, we show that B56ϵ undergoes proteolytic cleavage. The cleavage of B56ϵ is mediated by caspase-3 and occurs on the carboxyl side of an evolutionarily conserved N-terminal “DKXD” motif. These results demonstrate that B56ϵ, a substrate of caspase-3, is an essential regulator of apoptosis. So far, we have identified an alternative translation isoform and a caspase cleavage product of B56ϵ. The significance of post-transcriptional regulation of B56ϵ is discussed.
    Journal of Biological Chemistry 11/2010; 285(45):34493-34502. · 4.65 Impact Factor
  • Scott Q Harper
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    ABSTRACT: Huntington disease is an incurable, dominant neurodegenerative disorder caused by polyglutamine repeat expansion in the huntingtin protein. Reducing mutant huntingtin expression may offer a treatment for Huntington disease. RNA interference has emerged as a powerful method to silence dominant disease genes. As such, it is being developed as a prospective Huntington disease therapy. Here I discuss the current progress and important remaining challenges of RNA interference therapy for Huntington disease.
    Archives of neurology 09/2009; 66(8):933-8. · 7.58 Impact Factor
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    ABSTRACT: The transcription factor REST silences neuronal gene expression in non-neuronal cells. In neurons, the protein is sequestered in the cytoplasm in part through binding to huntingtin. Polyglutamine expansions in huntingtin, which causes Huntington's disease (HD), abrogates REST-huntingtin binding. Consequently, REST translocates to the nucleus, occupies RE1 repressor sequences and decreases neuronal gene expression. In this work, we found that levels of several microRNAs (miRNAs) with upstream RE1 sites are decreased in HD patient cortices relative to healthy controls. Interestingly, one of these, the bifunctional brain enriched miR-9/miR-9*, targets two components of the REST complex: miR-9 targets REST and miR-9* targets CoREST. These data provide evidence for a double negative feedback loop between the REST silencing complex and the miRNAs it regulates.
    Journal of Neuroscience 01/2009; 28(53):14341-6. · 6.91 Impact Factor
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    ABSTRACT: Huntington's disease (HD) is a fatal, dominant neurodegenerative disease caused by a polyglutamine repeat expansion in exon 1 of the HD gene, which encodes the huntingtin protein. We and others have shown that RNAi is a candidate therapy for HD because expression of inhibitory RNAs targeting mutant human HD transgenes improved neuropathology and behavioral deficits in HD mouse models. Here, we developed shRNAs targeting conserved sequences in human HD and mouse HD homolog (HDh) mRNAs to initiate preclinical testing in a knockin mouse model of HD. We screened 35 shRNAs in vitro and subsequently narrowed our focus to three candidates for in vivo testing. Unexpectedly, two active shRNAs induced significant neurotoxicity in mouse striatum, although HDh mRNA expression was reduced to similar levels by all three. Additionally, a control shRNA containing mismatches also induced toxicity, although it did not reduce HDh mRNA expression. Interestingly, the toxic shRNAs generated higher antisense RNA levels, compared with the nontoxic shRNA. These results demonstrate that the robust levels of antisense RNAs emerging from shRNA expression systems can be problematic in the mouse brain. Importantly, when sequences that were toxic in the context of shRNAs were placed into artificial microRNA (miRNA) expression systems, molecular and neuropathological readouts of neurotoxicity were significantly attenuated without compromising mouse HDh silencing efficacy. Thus, miRNA-based approaches may provide more appropriate biological tools for expressing inhibitory RNAs in the brain, the implications of which are crucial to the development of RNAi for both basic biological and therapeutic applications.
    Proceedings of the National Academy of Sciences 05/2008; 105(15):5868-73. · 9.81 Impact Factor
  • Scott Q Harper, Pedro Gonzalez-Alegre
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    ABSTRACT: The ability to manipulate RNAi in cultured mammalian cells has provided scientists with a very powerful tool to influence gene expression. Neurons represent a cell type that initially displayed resistance to transduction by siRNAs or shRNA, when attempting to silence expression of endogenous genes. However, the development of lentiviral systems with that goal has facilitated the exogenous manipulation of RNAi in these postmitotic cells. Lentiviral-mediated RNAi experiments in cultured mammalian neurons can be designed to address a wide variety of biological questions or to test potential therapeutic hairpins before moving to treatment trials in vivo. We provide a practical approach to accomplish siRNA-mediated silencing of the disease-linked protein torsinA in primary neuronal cultures through the generation of lentiviral vectors expressing shRNAs.
    Methods in molecular biology (Clifton, N.J.) 02/2008; 442:95-112. · 1.29 Impact Factor
  • Developmental Biology - DEVELOP BIOL. 01/2008; 319(2):535-535.
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    ABSTRACT: Clathrin-coated vesicles (CCVs) are responsible for the endocytosis of multiple cargo, including synaptic vesicle membranes. We now describe a new CCV protein, termed connecdenn, that contains an N-terminal DENN (differentially expressed in neoplastic versus normal cells) domain, a poorly characterized protein module found in multiple proteins of unrelated function and a C-terminal peptide motif domain harboring three distinct motifs for binding the alpha-ear of the clathrin adaptor protein 2 (AP-2). Connecdenn coimmunoprecipitates and partially colocalizes with AP-2, and nuclear magnetic resonance and peptide competition studies reveal that all three alpha-ear-binding motifs contribute to AP-2 interactions. In addition, connecdenn contains multiple Src homology 3 (SH3) domain-binding motifs and coimmunoprecipitates with the synaptic SH3 domain proteins intersectin and endophilin A1. Interestingly, connecdenn is enriched on neuronal CCVs and is present in the presynaptic compartment of neurons. Moreover, connecdenn has a uniquely stable association with CCV membranes because it resists extraction with Tris and high-salt buffers, unlike most other CCV proteins, but it is not detected on purified synaptic vesicles. Together, these observations suggest that connecdenn functions on the endocytic limb of the synaptic vesicle cycle. Accordingly, disruption of connecdenn interactions with its binding partners through overexpression of the C-terminal peptide motif domain or knock down of connecdenn through lentiviral delivery of small hairpin RNA both lead to defects in synaptic vesicle endocytosis in cultured hippocampal neurons. Thus, we identified connecdenn as a component of the endocytic machinery functioning in synaptic vesicle endocytosis, providing the first evidence of a role for a DENN domain-containing protein in endocytosis.
    Journal of Neuroscience 01/2007; 26(51):13202-12. · 6.91 Impact Factor
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    ABSTRACT: RNA interference (RNAi) occurs naturally in plant and animal cells as a means for modulating gene expression. This process has been experimentally manipulated to achieve targeted gene silencing in cells, tissues, and animals, using a variety of vector systems. Here, we tested the hypothesis that vectors based on feline immunodeficiency virus (FIV) could be used for coexpression of reporter constructs and RNAi expression cassettes. We found, unexpectedly, in our initial constructs that placement of RNAi expression cassettes downstream from a polymerase II (pol II)-expressed reporter gene inhibited reporter expression but not vector titer. Through a series of intermediate vector constructs, we found that placement of the RNAi expression cassette relative to the Rev response element and the pol II expression cassette was critical for efficient RNAi and reporter gene expression. These results suggested that steric factors, including RNA structure and recruitment of competing transcriptional machinery, may affect gene expression from FIV vectors. In a second series of studies, we show that target sequence silencing can be achieved in cells transduced by FIV vectors coexpressing reporter genes and 3' untranslated region resident microRNAs. The optimized FIV-based RNAi expression vectors will find broad use given the extensive tropism of pseudotyped FIV vectors for many cell types in vitro and in vivo.
    Journal of Virology 11/2006; 80(19):9371-80. · 5.08 Impact Factor

Publication Stats

2k Citations
248.37 Total Impact Points

Institutions

  • 2011–2014
    • Nationwide Children's Hospital
      • Center for Gene Therapy
      Columbus, Ohio, United States
  • 2008–2012
    • The Ohio State University
      • Department of Pediatrics
      Columbus, Ohio, United States
  • 2004–2009
    • University of Iowa
      • • Department of Internal Medicine
      • • Department of Molecular Physiology and Biophysics
      Iowa City, IA, United States
    • Muscular Dystrophy Association
      Tucson, Arizona, United States
  • 2002–2005
    • University of Washington Seattle
      • Department of Neurology
      Seattle, Washington, United States