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Jiang HC, Park SJ, Wang IH, Bear DM, Nowlan A, Greer PL. CD20/MS4A1 is a mammalian olfactory receptor expressed in a subset of olfactory sensory neurons that mediates innate avoidance of predators. Nat Commun 2024; 15:3360. [PMID: 38637611 PMCID: PMC11026480 DOI: 10.1038/s41467-024-47698-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 04/05/2024] [Indexed: 04/20/2024] Open
Abstract
The mammalian olfactory system detects and discriminates between millions of odorants to elicit appropriate behavioral responses. While much has been learned about how olfactory sensory neurons detect odorants and signal their presence, how specific innate, unlearned behaviors are initiated in response to ethologically relevant odors remains poorly understood. Here, we show that the 4-transmembrane protein CD20, also known as MS4A1, is expressed in a previously uncharacterized subpopulation of olfactory sensory neurons in the main olfactory epithelium of the murine nasal cavity and functions as a mammalian olfactory receptor that recognizes compounds produced by mouse predators. While wildtype mice avoid these predator odorants, mice genetically deleted of CD20 do not appropriately respond. Together, this work reveals a CD20-mediated odor-sensing mechanism in the mammalian olfactory system that triggers innate behaviors critical for organismal survival.
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Affiliation(s)
- Hao-Ching Jiang
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Sung Jin Park
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - I-Hao Wang
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Interdisciplinary Graduate Program, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Daniel M Bear
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Palo Alto, CA, USA
| | - Alexandra Nowlan
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Paul L Greer
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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Park SJ, Wang IH, Lee N, Jiang HC, Uemura T, Futai K, Kim D, Macosko E, Greer P. Combinatorial expression of neurexin genes regulates glomerular targeting by olfactory sensory neurons. bioRxiv 2024:2024.04.01.587570. [PMID: 38617205 PMCID: PMC11014570 DOI: 10.1101/2024.04.01.587570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Precise connectivity between specific neurons is essential for the formation of the complex neural circuitry necessary for executing intricate motor behaviors and higher cognitive functions. While trans -interactions between synaptic membrane proteins have emerged as crucial elements in orchestrating the assembly of these neural circuits, the synaptic surface proteins involved in neuronal wiring remain largely unknown. Here, using unbiased single-cell transcriptomic and mouse genetic approaches, we uncover that the neurexin family of genes enables olfactory sensory neuron (OSNs) axons to form appropriate synaptic connections with their mitral and tufted (M/T) cell synaptic partners, within the mammalian olfactory system. Neurexin isoforms are differentially expressed within distinct populations of OSNs, resulting in unique pattern of neurexin expression that is specific to each OSN type, and synergistically cooperate to regulate axonal innervation, guiding OSN axons to their designated glomeruli. This process is facilitated through the interactions of neurexins with their postsynaptic partners, including neuroligins, which have distinct expression patterns in M/T cells. Our findings suggest a novel mechanism underpinning the precise assembly of olfactory neural circuits, driven by the trans -interaction between neurexins and their ligands.
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Jiang HC, Park SJ, Wang IH, Bear DM, Nowlan A, Greer PL. CD20 is a mammalian odorant receptor expressed in a subset of olfactory sensory neurons that mediates innate avoidance of predators. Res Sq 2023:rs.3.rs-3290152. [PMID: 37790559 PMCID: PMC10543371 DOI: 10.21203/rs.3.rs-3290152/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The mammalian olfactory system detects and discriminates between millions of odorants to elicit appropriate behavioral responses. While much has been learned about how olfactory sensory neurons detect odorants and signal their presence, how specific innate, unlearned behaviors are initiated in response to ethologically relevant odors remains poorly understood. Here, we show that the 4-transmembrane protein CD20, also known as MS4A1, is expressed in a previously uncharacterized subpopulation of olfactory sensory neurons in the main olfactory epithelium of the murine nasal cavity and functions as a mammalian odorant receptor that recognizes compounds produced by mouse predators. While wild-type mice avoid these predator odorants, mice genetically deleted of CD20 do not appropriately respond. Together, this work reveals a novel CD20-mediated odor-sensing mechanism in the mammalian olfactory system that triggers innate behaviors critical for organismal survival.
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Affiliation(s)
- Hao-Ching Jiang
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Sung Jin Park
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - I-Hao Wang
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Interdisciplinary Graduate Program, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Daniel M Bear
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Current Affiliation: Wu Tsai Neurosciences Institute, Stanford University, Palo Alto, CA, USA
| | - Alexandra Nowlan
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Current affiliation: Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Paul L Greer
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
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Jiang HC, Park SJ, Wang IH, Bear DM, Nowlan A, Greer PL. CD20 is a mammalian odorant receptor expressed in a subset of olfactory sensory neurons that mediates innate avoidance of predators. bioRxiv 2023:2023.08.08.552498. [PMID: 37609248 PMCID: PMC10441374 DOI: 10.1101/2023.08.08.552498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The mammalian olfactory system detects and discriminates between millions of odorants to elicit appropriate behavioral responses. While much has been learned about how olfactory sensory neurons detect odorants and signal their presence, how specific innate, unlearned behaviors are initiated in response to ethologically relevant odors remains poorly understood. Here, we show that the 4-transmembrane protein CD20, also known as MS4A1, is expressed in a previously uncharacterized subpopulation of olfactory sensory neurons in the main olfactory epithelium of the murine nasal cavity and functions as a mammalian odorant receptor that recognizes compounds produced by mouse predators. While wild-type mice avoid these predator odorants, mice genetically deleted of CD20 do not appropriately respond. Together, this work reveals a novel CD20-mediated odor-sensing mechanism in the mammalian olfactory system that triggers innate behaviors critical for organismal survival.
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Wang IH, Murray E, Andrews G, Jiang HC, Park SJ, Donnard E, Durán-Laforet V, Bear DM, Faust TE, Garber M, Baer CE, Schafer DP, Weng Z, Chen F, Macosko EZ, Greer PL. Spatial transcriptomic reconstruction of the mouse olfactory glomerular map suggests principles of odor processing. Nat Neurosci 2022; 25:484-492. [PMID: 35314823 PMCID: PMC9281876 DOI: 10.1038/s41593-022-01030-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 02/07/2022] [Indexed: 12/14/2022]
Abstract
The olfactory system's ability to detect and discriminate between the vast array of chemicals present in the environment is critical for an animal's survival. In mammals, the first step of this odor processing is executed by olfactory sensory neurons, which project their axons to a stereotyped location in the olfactory bulb (OB) to form glomeruli. The stereotyped positioning of glomeruli in the OB suggests an importance for this organization in odor perception. However, because the location of only a limited subset of glomeruli has been determined, it has been challenging to determine the relationship between glomerular location and odor discrimination. Using a combination of single-cell RNA sequencing, spatial transcriptomics and machine learning, we have generated a map of most glomerular positions in the mouse OB. These observations significantly extend earlier studies and suggest an overall organizational principle in the OB that may be used by the brain to assist in odor decoding.
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Affiliation(s)
- I-Hao Wang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Evan Murray
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Greg Andrews
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Hao-Ching Jiang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sung Jin Park
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Elisa Donnard
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Violeta Durán-Laforet
- Department of Neurobiology and Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Daniel M Bear
- Department of Psychology, Stanford University, Palo Alto, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Palo Alto, CA, USA
| | - Travis E Faust
- Department of Neurobiology and Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Manuel Garber
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Christina E Baer
- Sanderson Center for Optical Imaging and Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dorothy P Schafer
- Department of Neurobiology and Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Fei Chen
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
| | - Evan Z Macosko
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA
| | - Paul L Greer
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
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Wang SY, Pollina EA, Wang IH, Pino LK, Bushnell HL, Takashima K, Fritsche C, Sabin G, Garcia BA, Greer PL, Greer EL. Role of epigenetics in unicellular to multicellular transition in Dictyostelium. Genome Biol 2021; 22:134. [PMID: 33947439 PMCID: PMC8094536 DOI: 10.1186/s13059-021-02360-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/22/2021] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The evolution of multicellularity is a critical event that remains incompletely understood. We use the social amoeba, Dictyostelium discoideum, one of the rare organisms that readily transits back and forth between both unicellular and multicellular stages, to examine the role of epigenetics in regulating multicellularity. RESULTS While transitioning to multicellular states, patterns of H3K4 methylation and H3K27 acetylation significantly change. By combining transcriptomics, epigenomics, chromatin accessibility, and orthologous gene analyses with other unicellular and multicellular organisms, we identify 52 conserved genes, which are specifically accessible and expressed during multicellular states. We validated that four of these genes, including the H3K27 deacetylase hdaD, are necessary and that an SMC-like gene, smcl1, is sufficient for multicellularity in Dictyostelium. CONCLUSIONS These results highlight the importance of epigenetics in reorganizing chromatin architecture to facilitate multicellularity in Dictyostelium discoideum and raise exciting possibilities about the role of epigenetics in the evolution of multicellularity more broadly.
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Affiliation(s)
- Simon Yuan Wang
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | | | - I-Hao Wang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Lindsay Kristina Pino
- Department of Biochemistry and Biophysics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Henry L Bushnell
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Ken Takashima
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Colette Fritsche
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - George Sabin
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Benjamin Aaron Garcia
- Department of Biochemistry and Biophysics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Paul Lieberman Greer
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Eric Lieberman Greer
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA.
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Chen YT, Wang IH, Wang YH, Chiu WY, Hu JH, Chen WH, Lee FJS. Action of Arl1 GTPase and golgin Imh1 in Ypt6-independent retrograde transport from endosomes to the trans-Golgi network. Mol Biol Cell 2019; 30:1008-1019. [PMID: 30726160 PMCID: PMC6589904 DOI: 10.1091/mbc.e18-09-0579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Arf and Rab/Ypt GTPases coordinately regulate membrane traffic and organelle structure by regulating vesicle formation and fusion. Ample evidence has indicated that proteins in these two families may function in parallel or complementarily; however, the manner in which Arf and Rab/Ypt proteins perform interchangeable functions remains unclear. In this study, we report that a Golgi-localized Arf, Arl1, could suppress Ypt6 dysfunction via its effector golgin, Imh1, but not via the lipid flippase Drs2. Ypt6 is critical for the retrograde transport of vesicles from endosomes to the trans-Golgi network (TGN), and its mutation leads to severe protein mislocalization and growth defects. We first overexpress the components of the Arl3-Syt1-Arl1-Imh1 cascade and show that only Arl1 and Imh1 can restore endosome-to-TGN trafficking in ypt6-deleted cells. Interestingly, increased abundance of Arl1 or Imh1 restores localization of the tethering factor Golgi associated retrograde–protein (GARP) complex to the TGN in the absence of Ypt6. We further show that the N-terminal domain of Imh1 is critical for restoring GARP localization and endosome-to-TGN transport in ypt6-deleted cells. Together, our results reveal the mechanism by which Arl1-Imh1 facilitates the recruitment of GARP to the TGN and compensates for the endosome-to-TGN trafficking defects in dysfunctional Ypt6 conditions.
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Affiliation(s)
- Yan-Ting Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - I-Hao Wang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yi-Hsun Wang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Wan-Yun Chiu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Jen-Hao Hu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Wen-Hui Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Fang-Jen S Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan.,Department of Medical Research, National Taiwan University Hospital, Taipei 100, Taiwan.,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
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Abstract
The Arl3-Arl1 GTPase cascade plays important roles in vesicle trafficking at the late Golgi and endosomes. Subunits of the conserved oligomeric Golgi (COG) complex, a tethering factor, are important for endosome-to-Golgi transport and contribute to the efficient functioning of the cytoplasm-to-vacuole targeting (Cvt) pathway, a well-known selective autophagy pathway. According to our findings, the Arl3-Arl1 GTPase cascade co-operates with Cog8 to regulate the Cvt pathway via Atg9 trafficking. arl3cog8Δ and arl1cog8Δ exhibit profound defects in aminopeptidase I maturation in rich medium. In addition, the Arl3-Arl1 cascade acts on the Cvt pathway via dynamic nucleotide binding. Furthermore, Atg9 accumulates at the late Golgi in arl3cog8Δ and arl1cog8Δ cells under normal growth conditions but not under starvation conditions. Thus, our results offer insight into the requirement for multiple components in the Golgi-endosome system to determine Atg9 trafficking at the Golgi, thereby regulating selective autophagy.
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Affiliation(s)
- I-Hao Wang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Jie Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jia-Wei Hsu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Fang Jen Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
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Wu MM, Chiou HY, Wang TW, Hsueh YM, Wang IH, Chen CJ, Lee TC. Association of blood arsenic levels with increased reactive oxidants and decreased antioxidant capacity in a human population of northeastern Taiwan. Environ Health Perspect 2001; 109:1011-7. [PMID: 11675266 PMCID: PMC1242077 DOI: 10.1289/ehp.011091011] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Arsenic is a notorious environmental toxicant known as both a carcinogen and an atherogen in human beings, but the pathogenic mechanisms are not completely understood. In cell culture studies, trivalent arsenic enhanced oxidative stress in a variety of mammalian cells, and this association may be closely associated with the development of arsenic-related diseases. To investigate the effect of arsenic exposure on oxidative stress in humans, we conducted a population study to determine the relationships of blood arsenic to reactive oxidants and antioxidant capacity at the individual level. We recruited 64 study subjects ages 42-75 years from residents of the Lanyang Basin on the northeast coast of Taiwan, where arsenic content in well water varies from 0 to > or = 3,000 microg/L. We used a chemiluminescence method, with lucigenin as an amplifier for measuring superoxide, to measure the plasma level of reactive oxidants. We used the azino-diethyl-benzthiazoline sulphate method to determine the antioxidant capacity level in plasma of each study subject. We determined arsenic concentration in whole blood by hydride formation with an atomic absorption spectrophotometer. The average arsenic concentration in whole blood of study subjects was 9.60 +/- 9.96 microg/L (+/- SD) with a range from 0 to 46.50 microg/L. The level of arsenic concentration in whole blood of study subjects showed a positive association with the level of reactive oxidants in plasma (r = +0.41, p = 0.001) and an inverse relationship with the level of plasma antioxidant capacity (r = -0.30, p = 0.014). However, we found no significant association (p = 0.266) between levels of plasma reactive oxidants and antioxidant capacity. Our results also show that the lower the primary arsenic methylation capability, the lower the level of plasma antioxidant capacity (p = 0.029). These results suggest that ingestion of arsenic-contaminated well water may cause deleterious effects by increasing the level of reactive oxidants and decreasing the level of antioxidant capacity in plasma of individuals. Persistent oxidative stress in peripheral blood may be a mechanism underlying the carcinogenesis and atherosclerosis induced by long-term arsenic exposure.
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Affiliation(s)
- M M Wu
- Institute of Biomedical Sciences, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan, Republic of China
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Sun CT, Lo WY, Wang IH, Lo YH, Shiou SR, Lai CK, Ting LP. Transcription repression of human hepatitis B virus genes by negative regulatory element-binding protein/SON. J Biol Chem 2001; 276:24059-67. [PMID: 11306577 DOI: 10.1074/jbc.m101330200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A negative regulatory element (NRE) is located immediately upstream of the upstream regulatory sequence of core promoter and second enhancer of human hepatitis B virus (HBV). NRE represses the transcription activation function of the upstream regulatory sequence of core promoter and the second enhancer. In this study, we described the cloning and characterization of an NRE-binding protein (NREBP) through expression cloning. NREBP cDNA is 8266 nucleotides in size and encodes a protein of 2386 amino acids with a predicted molecular mass of 262 kDa. Three previously described cDNAs, DBP-5, SONB, and SONA, are partial sequence and/or alternatively spliced forms of NREBP. The genomic locus of the NREBP/SON gene is composed of 13 exons and 12 introns. The endogenous NREBP protein is localized in the nucleus of human hepatoma HuH-7 cells. Antibody against NREBP protein can specifically block the NRE binding activity present in fractionated nuclear extracts in gel shifting assays, indicating that NREBP is the endogenous nuclear protein that binds to NRE sequence. By polymerase chain reaction-assisted binding site selection assay, we determined that the consensus sequence for NREBP binding is GA(G/T)AN(C/G)(A/G)CC. Overexpression of NREBP enhances the repression of the HBV core promoter activity via NRE. Overexpression of NREBP can also repress the transcription of HBV genes and the production of HBV virions in a transient transfection system that mimics the viral infection in vivo.
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Affiliation(s)
- C T Sun
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan, Republic of China
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Wang IH, Subramanian V, Moorman R, Burleson J, Ko J. Chiral high-performance liquid chromatography of N-octyl bicycloheptene dicarboximide and confirmatory studies using liquid chromatography-tandem mass spectrometry and two-dimensional nuclear magnetic resonance spectroscopy. J Chromatogr A 1999; 864:271-81. [PMID: 10669295 DOI: 10.1016/s0021-9673(99)01044-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N-Octyl bicycloheptene dicarboximide (MGK 264) has exo and endo diastereomers. Each structure has a chiral center at the nitrogen side chain. Enantioselective separation of MGK 264 was achieved by normal-phase high-performance liquid chromatography (HPLC) using cellulose-based Chiralcel OD column with diode-array and optical rotation detectors. Peaks were isolated with the purpose of identifying their stereochemical structures. Molecular mass of the HPLC peaks and their structural information was determined by liquid chromatography-electrospray tandem mass spectrometry (LC-ES-MS-MS). A two-dimensional nuclear magnetic resonance (NMR) spectroscopic technique was used to establish the structural features. Correlation of the data obtained from chiral separation and NMR facilitated in unambiguous assignment of the HPLC peaks.
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Affiliation(s)
- I H Wang
- Wellmark International, Inc., Dallas, TX 75234, USA
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