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Foehring RC, Guan D, Toleman T, Cantrell AR. Whole cell recording from an organotypic slice preparation of neocortex. J Vis Exp 2011:2600. [PMID: 21673642 PMCID: PMC3197031 DOI: 10.3791/2600] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
We have been studying the expression and functional roles of voltage-gated potassium channels in pyramidal neurons from rat neocortex. Because of the lack of specific pharmacological agents for these channels, we have taken a genetic approach to manipulating channel expression. We use an organotypic culture preparation (16) in order to maintain cell morphology and the laminar pattern of cortex. We typically isolate acute neocortical slices at postnatal days 8-10 and maintain the slices in culture for 3-7 days. This allows us to study neurons at a similar age to those in our work with acute slices and minimizes the development of exuberant excitatory connections in the slice. We record from visually-identified pyramidal neurons in layers II/III or V using infrared illumination (IR-) and differential interference contrast microscopy (DIC) with whole cell patch clamp in current- or voltage-clamp. We use biolistic (Gene gun) transfection of wild type or mutant potassium channel DNA to manipulate expression of the channels to study their function. The transfected cells are easily identified by epifluorescence microscopy after co-transfection with cDNA for green fluorescent protein (GFP). We compare recordings of transfected cells to adjacent, untransfected neurons in the same layer from the same slice.
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Affiliation(s)
- Robert C Foehring
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, USA.
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2
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Lithium chloride regulation of the substance P encoding preprotachykinin a, Tac1 gene in rat hippocampal primary cells. J Mol Neurosci 2010; 45:94-100. [PMID: 20690045 DOI: 10.1007/s12031-010-9431-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 07/19/2010] [Indexed: 12/26/2022]
Abstract
In rat hippocampal cultures, the preprotachykinin A (PPTA/Tac1) gene, which encodes the neuropeptide substance P, is regulated by the action of lithium. We used reporter gene and expression constructs to demonstrate that this mechanism of action of lithium is mediated via a previously characterised cis-regulatory Ebox element in the proximal promoter, which binds members of the basic Helix-Loop-Helix family of transcription factors. Consistent with this, in hippocampal cells, both the expression of the endogenous gene and the function of this promoter element are differentially regulated by the basic Helix-Loop-Helix factors, upstream stimulatory factor 1 and 2 (USF1/2). In addition, the genes for USF1 and USF2 are differentially regulated by lithium in these cells. Our data implicate USF1 as a major regulator of the action of lithium on the proximal PPTA promoter.
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Hilton KJ, Bateson AN, King AE. Neurotrophin-induced preprotachykinin-A gene promoter modulation in organotypic rat spinal cord culture. J Neurochem 2006; 98:690-9. [PMID: 16893415 DOI: 10.1111/j.1471-4159.2006.03910.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To study regulation of the preprotachykinin-A gene promoter, we utilised a biolistic gene transfer protocol to deliver a DNA construct that incorporates a portion of the preprotachykinin-A gene promoter and an enhanced green fluorescent protein reporter gene into neonatal rat spinal cord organotypic slices. The ability of the neurokinin-1 receptor agonist [Sar9,Met(O2)11]-substance P, nerve growth factor and brain derived neurotrophic factor to modulate positively preprotachykinin-A gene promoter construct activity, as indicated by de novo enhanced green fluorescent protein expression, was determined. Treatment of organotypic slices with [Sar9, Met(O2)11]-substance P (10 microm, P < 0.05), nerve growth factor (200 ng/mL, P < 0.001) or brain derived neurotrophic factor (200 ng/mL, P < 0.02) significantly increased the proportion of cytomegaloviral promoter-DsRed transfected cells (used to visualise total transfected cells) that co-expressed enhanced green fluorescent protein. The distribution of enhanced green fluorescent protein/DsRed-positive neurones across spinal laminae was broadly in line with the known distribution of spinal Trk and neurokinin-1 receptors. These data suggest a modulated activity of the preprotachykinin-A gene promoter in spinal neurones in vitro by substance P and/or neurotrophins. The functional consequences of such transcriptional changes within central peptidergic circuitry and their relevance to chronic pain are considered.
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Affiliation(s)
- Kathryn J Hilton
- Institute of Membrane and Systems Biology, University of Leeds, Leeds, UK
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Guindalini C, Howard M, Haddley K, Laranjeira R, Collier D, Ammar N, Craig I, O’Gara C, Bubb VJ, Greenwood T, Kelsoe J, Asherson P, Murray RM, Castelo A, Quinn JP, Vallada H, Breen G. A dopamine transporter gene functional variant associated with cocaine abuse in a Brazilian sample. Proc Natl Acad Sci U S A 2006; 103:4552-7. [PMID: 16537431 PMCID: PMC1450209 DOI: 10.1073/pnas.0504789103] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The dopamine (DA) transporter DAT1 is a major target bound by cocaine in brain. We examined the influence of functional genetic variants in DAT1 on cocaine addiction. Repeat polymorphisms, including a 30-bp variable-number tandem repeat (VNTR) in intron 8 (Int8 VNTR) with two common alleles, were genotyped in cocaine-dependent abusers (n = 699) and in controls with no past history of drug abuse (n = 866) from São Paulo, Brazil. Positive association was observed with allele 3 of the Int8 VNTR and cocaine abuse (allele odds ratio = 1.2, 95% confidence interval = 1.01-1.37, P = 0.036; 3/3 homozygote odds ratio = 1.45, 95% confidence interval = 1.18-1.78, P = 0.0008). Population stratification was assessed and did not affect the results. Haplotypic analyses using additional polymorphisms indicated that the Int8 VNTR is responsible for the observed association. Functional analyses in reporter-gene constructs, demonstrated that allele 3 mediates significant (P < 0.05) but small reduced expression compared with the "protective" allele 2. This difference increased when 1 and 10 muM cocaine was added to the cell culture ( approximately 40% reduction of the 3 allele expression versus the 2 allele). The 3 allele also demonstrated approximately 3-fold-increased expression over the 2 allele in response to KCl plus forskolin challenge. We demonstrate a robust association between cocaine dependence and a VNTR allele in SLC6A3, conferring a small but detectable effect, and we show that this VNTR may be functional. This study suggests that DAT1 gene variation may play a role in cocaine dependence etiology.
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Affiliation(s)
- Camila Guindalini
- Medical Research Council Social Genetic and Developmental Psychiatry Research Centre
- Institute of Psychiatry, University of São Paulo Medical School, 01422-000 São Paulo, Brazil
| | - Mark Howard
- Departments of Physiology and
- Human Anatomy and Cell Biology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Kate Haddley
- Departments of Physiology and
- Human Anatomy and Cell Biology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Ronaldo Laranjeira
- Unit of Drug and Alcohol Research, Department of Psychiatry, Federal University of São Paulo, 04023-900 São Paulo, Brazil
| | - David Collier
- Medical Research Council Social Genetic and Developmental Psychiatry Research Centre
- Division of Psychological Medicine, and
| | - Nik Ammar
- Medical Research Council Social Genetic and Developmental Psychiatry Research Centre
| | - Ian Craig
- Medical Research Council Social Genetic and Developmental Psychiatry Research Centre
| | - Colin O’Gara
- Division of Psychological Medicine, and
- National Addiction Centre, Institute of Psychiatry, King’s College London, London SE5 8AF, United Kingdom
| | - Vivian J. Bubb
- Departments of Physiology and
- Human Anatomy and Cell Biology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Tiffany Greenwood
- Department of Psychiatry, University of California at San Diego, La Jolla, CA 92093; and
| | - John Kelsoe
- Department of Psychiatry, University of California at San Diego, La Jolla, CA 92093; and
- Department of Psychiatry, San Diego Veterans Affairs Healthcare System, La Jolla, CA 92093
| | - Phil Asherson
- Medical Research Council Social Genetic and Developmental Psychiatry Research Centre
| | | | - Adauto Castelo
- Unit of Drug and Alcohol Research, Department of Psychiatry, Federal University of São Paulo, 04023-900 São Paulo, Brazil
| | - John P. Quinn
- Departments of Physiology and
- Human Anatomy and Cell Biology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Homero Vallada
- Division of Psychological Medicine, and
- Institute of Psychiatry, University of São Paulo Medical School, 01422-000 São Paulo, Brazil
| | - Gerome Breen
- Medical Research Council Social Genetic and Developmental Psychiatry Research Centre
- Division of Psychological Medicine, and
- To whom correspondence should be addressed at:
Section of Genetics, Medical Research Council Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, Kings College London, Room 222, Social, Genetic, and Developmental Psychiatry Centre, P.O. Box 81, London SE5 8AF, United Kingdom. E-mail:
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5
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Hilton KJ, Bateson AN, King AE. A model of organotypic rat spinal slice culture and biolistic transfection to elucidate factors that drive the preprotachykinin-A promoter. ACTA ACUST UNITED AC 2004; 46:191-203. [PMID: 15464207 DOI: 10.1016/j.brainresrev.2004.07.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2004] [Indexed: 11/25/2022]
Abstract
The tachykinin substance P (SP) is a neuropeptide that is expressed in some nociceptive primary sensory afferents and in discrete populations of spinal cord neurons. Expression of spinal SP and the preprotachykinin-A (PPT-A) gene that encodes SP exhibits plasticity in response to conditions such as peripheral inflammation but the mechanisms that regulate expression are poorly understood. We have developed a spinal cord organotypic culture system that is suitable for the analysis of PPT-A gene promoter activity following biolistic transfection of recombinant DNA constructs. Spinal cord organotypic slices showed good viability over a 7-day culture period. Immunostaining for phenotypic markers such as NeuN and beta-III tubulin demonstrated preservation of neurons and their structure, although there was evidence of axotomy-induced down-regulation of NeuN in certain neuronal populations. Neurokinin-1 receptor (NK-1R) immunostaining in laminae I and III was similar to that seen in acute slices. Biolistic transfection was used to introduce DNA constructs into neurons of these organotypic cultures. Following transfection with a construct in which expression of enhanced green fluorescent protein (EGFP) is controlled by the PPT-A promoter, we showed that induction of neuronal activity by administration of a forskolin analogue/high K(+) (10 microM/10 mM) for 24 h resulted in a fourfold increase in the number of EGFP-positive cells. Similarly, a twofold increase was obtained after treatment with the NK-1R-specific agonist [Sar(9),Met (O(2))(11)]-substance P (10 microM). These data demonstrate the usefulness of this model to study physiological and pharmacological factors relevant to nociceptive processing that can modulate PPT-A promoter activity.
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Affiliation(s)
- Kathryn J Hilton
- School of Biomedical Sciences, University of Leeds, Clarendon Way, Leeds, LS2 9JT, UK
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Béïque JC, Campbell B, Perring P, Hamblin MW, Walker P, Mladenovic L, Andrade R. Serotonergic regulation of membrane potential in developing rat prefrontal cortex: coordinated expression of 5-hydroxytryptamine (5-HT)1A, 5-HT2A, and 5-HT7 receptors. J Neurosci 2004; 24:4807-17. [PMID: 15152041 PMCID: PMC6729457 DOI: 10.1523/jneurosci.5113-03.2004] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The developing prefrontal cortex receives a dense serotonergic innervation, yet little is known about the actions of serotonin [5-Hydroxytryptamine (5-HT)] in this region during development. Here, we examined the developmental regulation of 5-HT receptors controlling the excitability of pyramidal neurons of this region. Using whole-cell recordings in in vitro brain slices, we identified a dramatic shift in the effects of 5-HT on membrane potential during the postnatal developmental period. In slices derived from young animals [postnatal day (P) 6 to P19], administration of 5-HT elicits a robust depolarization of layer V pyramidal neurons, which gradually shifts to a hyperpolarization commencing during the third postnatal week. This progression is the result of coordinated changes in the function of 5-HT7 and 5-HT2A receptors, which mediate different aspects of the depolarization, and of 5-HT1A receptors, which signal the late developing hyperpolarization. The loss of the 5-HT7 receptor-mediated depolarization and the appearance of the 5-HT1A receptor-mediated hyperpolarization appears to reflect changes in receptor expression. In contrast, the decline in the 5-HT2A receptor depolarization with increasing age was associated with changes in the effectiveness with which these receptors could elicit a membrane depolarization, rather than loss of the receptors per se. Together, these results outline coordinated changes in the serotonergic regulation of cortical excitability at a time of extensive synaptic development and thus suggest a key role for these receptor subtypes in the postnatal development of the prefrontal cortex.
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MESH Headings
- Age Factors
- Animals
- G Protein-Coupled Inwardly-Rectifying Potassium Channels
- Gene Expression Regulation, Developmental/physiology
- In Situ Hybridization
- In Vitro Techniques
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Neurons/drug effects
- Neurons/metabolism
- Patch-Clamp Techniques
- Potassium Channels/metabolism
- Potassium Channels, Inwardly Rectifying
- Prefrontal Cortex/drug effects
- Prefrontal Cortex/growth & development
- Prefrontal Cortex/metabolism
- Pyramidal Cells/drug effects
- Pyramidal Cells/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT1A/biosynthesis
- Receptor, Serotonin, 5-HT1A/genetics
- Receptor, Serotonin, 5-HT2A/biosynthesis
- Receptor, Serotonin, 5-HT2A/genetics
- Receptors, Serotonin/biosynthesis
- Receptors, Serotonin/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Serotonin/pharmacology
- Serotonin/physiology
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Affiliation(s)
- Jean-Claude Béïque
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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7
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Bouhamdan M, Michelhaugh SK, Calin-Jageman I, Ahern-Djamali S, Bannon MJ. Brain-specific RGS9-2 is localized to the nucleus via its unique proline-rich domain. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1691:141-50. [PMID: 15110994 DOI: 10.1016/j.bbamcr.2004.01.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2003] [Revised: 01/14/2004] [Accepted: 01/15/2004] [Indexed: 01/03/2023]
Abstract
Brain-specific regulator of G protein signaling 9 (RGS9-2) is a member of a family of proteins that can function as GTPase-activating proteins for heterotrimeric G proteins. In the present study, we examined the intracellular distribution of RGS9-2 in native brain tissue and transfected cells. Immunocytochemical and immunoblot experiments revealed an unexpectedly high proportion of RGS9-2 within the nuclei of forebrain neurons. A similar intracellular distribution was seen in transfected COS-7 cells. The RGS9 binding partner G(beta5) further enhanced the nuclear localization of RGS9-2, but did not affect the strongly cytoplasmic localization of RGS9-1, the retinal form of RGS9. Deletion construct analysis revealed that the unique polyproline-rich C-terminus of brain-specific RGS9-2 contains sequences necessary and sufficient to target RGS9 to the nucleus of COS-7 cells, as well as cultured striatal neurons. Furthermore, RGS9-2 transfection increased the transcriptional activity of a neuronal gene construct normally expressed in RGS9-positive neurons, suggesting that nuclear RGS9 directly or indirectly regulates transcription in vivo. The nuclear localization of RGS9-2 suggests a heretofore-unanticipated role for this brain-specific protein in transducing signals to the nuclei of forebrain neurons.
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Affiliation(s)
- Mohamad Bouhamdan
- Department of Psychiatry, Wayne State University School of Medicine, 540 E. Canfield, 2309 Scott Hall, Detroit, MI 48201, USA
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8
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Gao XB, Ghosh PK, van den Pol AN. Neurons Synthesizing Melanin-Concentrating Hormone Identified by Selective Reporter Gene Expression After Transfection In Vitro: Transmitter Responses. J Neurophysiol 2003; 90:3978-85. [PMID: 14573562 DOI: 10.1152/jn.00593.2003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons from the lateral hypothalamus that synthesize melanin-concentrating hormone (MCH) play an important role in the regulation of energy homeostasis. Relatively little is known of the cellular physiology and transmitter responses of these neurons, in part because of the difficulty in identifying live MCH cells. Here we use a novel approach of transfection of specific gene constructs with the MCH promoter driving green fluorescent protein (GFP) or red fluorescent protein (dsRed2) in CNS cultures to identify live rat MCH neurons; all neurons expressing the reporter gene showed MCH immunoreactivity, indicating selective expression. MCH neurons had a resting membrane potential of –57.5 ± 0.6 mV, a linear current-voltage relation and a mean input resistance of 1,013 MΩ. Long depolarizing pulses revealed significant spike frequency adaptation. Functional glutamate and GABA receptors were expressed by MCH neurons. MCH neurons were hyperpolarized by norepinephrine in the presence or absence of tetrodotoxin, suggesting direct inhibition. Orexigenic peptides neuropeptide Y (NPY) and MCH showed no direct effect on membrane potential, input resistance, action potential width, or afterhyperpolarization potential, but inhibited voltage-dependent calcium channels, indicating that MCH neurons expressed both MCH and NPY receptors.
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Affiliation(s)
- Xiao-Bing Gao
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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9
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Abstract
PSD-95 is one of the most abundant proteins found in the postsynaptic density of excitatory synapses. However, the precise functional role played by PSD-95 in regulating synaptic transmission and plasticity remains undefined. To address this issue, we have overexpressed PSD-95 in cortical pyramidal neurons in organotypic brain slices using particle-mediated gene transfer and assessed the consequences on synaptic transmission and plasticity. The AMPA receptor/NMDA receptor (AMPAR/NMDAR) ratio of evoked EPSCs recorded at +40 mV was greater in PSD-95-transfected pyramidal neurons than in controls. This difference could not be accounted for by a change in rectification of AMPAR-mediated synaptic currents since the current-voltage curves obtained in controls and in PSD-95-transfected neurons were indistinguishable. However, the amplitude of AMPAR-mediated evoked EPSCs was larger in PSD-95-transfected neurons compared to matched controls. Paired-pulse ratio analysis suggested that overexpression of PSD-95 did not alter presynaptic release probability. Transfection of PSD-95 was further accompanied by an increase in the frequency, but not amplitude, of AMPAR-mediated mEPSCs. Together, these results indicate that transfection of PSD-95 increased AMPAR-mediated synaptic transmission. Furthermore, they suggest that this phenomenon reflects an increased number of synapses expressing AMPARs rather than an increased number or function of these receptors at individual synapses. We tested the consequences of these changes on synaptic plasticity and found that PSD-95 transfection greatly enhanced the probability of observing long-term depression. These results thus identify a physiological role for PSD-95 and demonstrate that this protein can play a decisive role in controlling synaptic strength and activity-dependent synaptic plasticity.
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Affiliation(s)
- Jean-Claude Béïque
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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10
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Michelhaugh SK, Fiskerstrand C, Lovejoy E, Bannon MJ, Quinn JP. The dopamine transporter gene (SLC6A3) variable number of tandem repeats domain enhances transcription in dopamine neurons. J Neurochem 2001; 79:1033-8. [PMID: 11739616 DOI: 10.1046/j.1471-4159.2001.00647.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The dopamine (DAT) and serotonin (SERT) transporter genes both contain variable number of tandem repeats (VNTR) in non-coding gene regions which have been correlated with a predisposition to a variety of CNS disorders. There is considerable homology between individual DAT and SERT repeat DNA sequences, which is reflected in their ability to compete with each other for specific protein binding as demonstrated by electrophoretic mobility shift assay. The SERT VNTR has recently been shown to act as a transcriptional enhancer. Because of the similarities between SERT and DAT VNTRs, the DAT VNTR may also enhance transcription. This study demonstrates by lipid transfection into an immortalized dopaminergic cell line and biolistic transfection into dopamine neurons in neonatal rat midbrain slices that the human nine-repeat DAT VNTR can enhance transcription. This enhancing activity suggests that the DAT VNTR may play a role in regulation of DAT gene expression.
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Affiliation(s)
- S K Michelhaugh
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, USA
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11
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Campbell BM, Walker PD. Striatal preprotachykinin mRNA levels are regulated by stimulatory agents and dopamine D1 receptor manipulation in rodent organotypic slice cultures. Brain Res 2001; 888:26-33. [PMID: 11146049 DOI: 10.1016/s0006-8993(00)02997-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have utilized an organotypic slice culture system to determine factors which directly influence the expression of striatal preprotachykinin (PPT) mRNA. Striatal slices were generated from 3-day-old male rat pups and cultured on Millicell-CM inserts in serum-containing media. Under these conditions, striatal PPT mRNA levels fell significantly (-55.7+/-6.2%) in slices cultured for 2 days in vitro (2DIV) as compared to slices placed in culture for 3 h (0DIV). However, striatal PPT mRNA expression did not decline further in 4DIV cultured slices (-59.6+/-7.1%). When 2DIV slices were exposed to combined high potassium (K(+), 10 mM) and forskolin (10 microM) stimulation for 3 h, PPT mRNA levels were increased within areas of the brain normally associated with tachykinin production. Application of the dopamine (DA) D1 receptor agonist SKF-38393 (10 microM) at 2DIV for 3 h also increased (+162.9+/-28.9%) PPT mRNA expression, but increases were localized within the striatum. SKF-38393-stimulated increases were completely blocked by the D1 antagonist SCH-23390 (10 microM), which alone had no effect on mRNA levels. However, a 3-h incubation with SKF-38393 on 0DIV slice cultures did not affect PPT mRNA expression whereas SCH-23390 decreased PPT message levels (-24.5+/-5.4%). These findings indicate that tachykinin gene expression is inducible within slice culture preparations and that the maintenance of normal striatal PPT mRNA levels depends on DA D1 receptor tone.
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Affiliation(s)
- B M Campbell
- Cellular and Clinical Neurobiology Program, Department of Psychiatry and Behavioral Neurosciences, Wayne State University, School of Medicine, Detroit, MI 48201, USA
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12
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Quinn JP, Fiskerstrand CE, Gerrard L, MacKenzie A, Payne CM. Molecular models to analyse preprotachykinin-A expression and function. Neuropeptides 2000; 34:292-302. [PMID: 11049733 DOI: 10.1054/npep.2000.0833] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Towards an understanding of the mechanisms controlling Preprotachykinin A (PPT) expression we have generated a variety of molecular models to determine the mechanisms regulating both the tissue-specific and stimulus-inducible expression of the PPT gene. The approaches used include transgenic and virus vector models complementing biochemical analysis of promoter interactions with transcription factors. We have identified and characterised a yeast artificial chromosome (YAC) containing the human PPT gene and generated transgenic mouse lines containing multiple copies of this chromosome on a normal mouse genetic background. This resulted in a pattern of expression in the nervous system remarkably similar to that reported for PPT mRNA in rodents. In addition, this transgenic model has been constructed in such a manner to allow for over expression of tachykinins based on the number of extra alleles in the transgenic mouse. These animals allow us to further examine the function of the tachykinins and acts as a useful complement to existing PPT ablated mice. In vitro we have introduced the proximal PPT promoter in reporter gene constructs into adult neurones in both DRG and the CNS by an adenoassociated virus (AAV) vector or by biolistic transfection respectively. Using the AAV vector we have demonstrated that the proximal promoter can mediate the effects of NGF in adult rat DRG. These models allow us to delineate transcriptional domains involved in the physiological and pathological expression of the PPT gene.
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Affiliation(s)
- J P Quinn
- Department of Veterinary Pathology, University of Edinburgh, Summerhall, UK.
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