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Cui R, Delclos PJ, Schumer M, Rosenthal GG. Early social learning triggers neurogenomic expression changes in a swordtail fish. Proc Biol Sci 2018; 284:rspb.2017.0701. [PMID: 28515207 DOI: 10.1098/rspb.2017.0701] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 04/18/2017] [Indexed: 01/06/2023] Open
Abstract
Mate choice can play a pivotal role in the nature and extent of reproductive isolation between species. Mating preferences are often dependent on an individual's social experience with adult phenotypes throughout development. We show that olfactory preference in a swordtail fish (Xiphophorus malinche) is affected by previous experience with adult olfactory signals. We compare transcriptome-wide gene expression levels of pooled sensory and brain tissues between three treatment groups that differ by social experience: females with no adult exposure, females exposed to conspecifics and females exposed to heterospecifics. We identify potential functionally relevant genes and biological pathways differentially expressed not only between control and exposure groups, but also between groups exposed to conspecifics and heterospecifics. Based on our results, we speculate that vomeronasal receptor type 2 paralogs may detect species-specific pheromone components and thus play an important role in reproductive isolation between species.
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Affiliation(s)
- Rongfeng Cui
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Pablo J Delclos
- Department of Biology, Texas A&M University, College Station, TX 77843, USA.,Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', Calnali, 43240 Hidalgo, Mexico
| | - Molly Schumer
- Department of Biology, Texas A&M University, College Station, TX 77843, USA.,Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', Calnali, 43240 Hidalgo, Mexico.,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Gil G Rosenthal
- Department of Biology, Texas A&M University, College Station, TX 77843, USA.,Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', Calnali, 43240 Hidalgo, Mexico
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Krasnec KV, Papenfuss AT, Miller RD. The UT family of MHC class I loci unique to non-eutherian mammals has limited polymorphism and tissue specific patterns of expression in the opossum. BMC Immunol 2016; 17:43. [PMID: 27825298 PMCID: PMC5101759 DOI: 10.1186/s12865-016-0181-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 10/28/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Major Histocompatibility Complex (MHC) class I family of genes encode for molecules that have well-conserved structures, but have evolved to perform diverse functions. The availability of the gray, short-tailed opossum, Monodelphis domestica whole genome sequence has allowed for analysis of MHC class I gene content in this marsupial. Utilization of a novel method to search for MHC related domain structures revealed a previously unknown family of MHC class I-related genes. These genes, named UT1-17, are clustered on chromosome 1 in the opossum, unlinked to the MHC region. UT genes are only found in marsupial and monotreme genomes, consistent with being ancient in mammals yet lost in eutherian mammals. This study investigates the expression and polymorphism of the UT loci in the opossum to gain insight into their possible function. RESULTS Of the 17 opossum UT genes, most have restricted tissue transcription patterns, with the thymus and skin being the most common sites. Full-length structure of 11 UT transcripts revealed genes varying between five and eight exons, typical for class I family members. There were only two alternative splice variants found. The UT genes also have limited polymorphism and little evidence of positive selection. One locus, UT8, was chosen for further analysis due to its conservation amongst marsupials and generic characteristics. UT8 transcription is limited to developing αβ thymocytes, and is absent from mature αβ T cells in peripheral lymphoid tissues. CONCLUSION The overall characteristics and features of UT genes including low polymorphism and restricted tissue expression make it likely that the molecules encoded by UT genes perform roles other than antigenic peptide presentation.
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Affiliation(s)
- Katina V Krasnec
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Anthony T Papenfuss
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Pde, Parkville, 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Australia.,Peter MacCallum Cancer Centre, East Melbourne, 3002, Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia
| | - Robert D Miller
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, NM, 87131, USA.
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Tao YX, Conn PM. Chaperoning G protein-coupled receptors: from cell biology to therapeutics. Endocr Rev 2014; 35:602-47. [PMID: 24661201 PMCID: PMC4105357 DOI: 10.1210/er.2013-1121] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 03/14/2014] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) are membrane proteins that traverse the plasma membrane seven times (hence, are also called 7TM receptors). The polytopic structure of GPCRs makes the folding of GPCRs difficult and complex. Indeed, many wild-type GPCRs are not folded optimally, and defects in folding are the most common cause of genetic diseases due to GPCR mutations. Both general and receptor-specific molecular chaperones aid the folding of GPCRs. Chemical chaperones have been shown to be able to correct the misfolding in mutant GPCRs, proving to be important tools for studying the structure-function relationship of GPCRs. However, their potential therapeutic value is very limited. Pharmacological chaperones (pharmacoperones) are potentially important novel therapeutics for treating genetic diseases caused by mutations in GPCR genes that resulted in misfolded mutant proteins. Pharmacoperones also increase cell surface expression of wild-type GPCRs; therefore, they could be used to treat diseases that do not harbor mutations in GPCRs. Recent studies have shown that indeed pharmacoperones work in both experimental animals and patients. High-throughput assays have been developed to identify new pharmacoperones that could be used as therapeutics for a number of endocrine and other genetic diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology, and Pharmacology (Y.-X.T.), College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519; and Departments of Internal Medicine and Cell Biology (P.M.C.), Texas Tech University Health Science Center, Lubbock, Texas 79430-6252
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A family of nonclassical class I MHC genes contributes to ultrasensitive chemodetection by mouse vomeronasal sensory neurons. J Neurosci 2014; 34:5121-33. [PMID: 24719092 DOI: 10.1523/jneurosci.0186-14.2014] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The mouse vomeronasal organ (VNO) has a pivotal role in chemical communication. The vomeronasal sensory neuroepithelium consists of distinct populations of vomeronasal sensory neurons (VSNs). A subset of VSNs, with cell bodies in the basal part of the basal layer, coexpress Vmn2r G-protein-coupled receptor genes with H2-Mv genes, a family of nine nonclassical class I major histocompatibility complex genes. The in vivo, physiological roles of the H2-Mv gene family remain mysterious more than a decade after the discovery of combinatorial H2-Mv gene expression in VSNs. Here, we have taken a genetic approach and have deleted the 530 kb cluster of H2-Mv genes in the mouse germline by chromosome engineering. Homozygous mutant mice (ΔH2Mv mice) are viable and fertile. There are no major anatomical defects in their VNO and accessory olfactory bulb (AOB). Their VSNs can be stimulated with chemostimuli (peptides and proteins) to the same maximum responses as VSNs of wild-type mice, but require much higher concentrations. This physiological phenotype is displayed at the single-cell level and is cell autonomous: single V2rf2-expressing VSNs, which normally coexpress H2-Mv genes, display a decreased sensitivity to a peptide ligand in ΔH2Mv mice, whereas single V2r1b-expressing VSNs, which do not coexpress H2-Mv genes, show normal sensitivity to a peptide ligand in ΔH2Mv mice. Consistent with the greatly decreased VSN sensitivity, ΔH2Mv mice display pronounced deficits in aggressive and sexual behaviors. Thus, H2-Mv genes are not absolutely essential for the generation of physiological responses, but are required for ultrasensitive chemodetection by a subset of VSNs.
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Adams EJ, Luoma AM. The adaptable major histocompatibility complex (MHC) fold: structure and function of nonclassical and MHC class I-like molecules. Annu Rev Immunol 2013; 31:529-61. [PMID: 23298204 DOI: 10.1146/annurev-immunol-032712-095912] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The MHC fold is found in proteins that have a range of functions in the maintenance of an organism's health, from immune regulation to fat metabolism. Well adapted for antigen presentation, as seen for peptides in the classical MHC molecules and for lipids in CD1 molecules, the MHC fold has also been modified to perform Fc-receptor activity (e.g., FcRn) and for roles in host homeostasis (e.g., with HFE and ZAG). The more divergent MHC-like molecules, such as some of those that interact with the NKG2D receptor, represent the minimal MHC fold, doing away with the α3 domain and β2m while maintaining the α1/α2 platform domain for receptor engagement. Viruses have also co-opted the MHC fold for immune-evasive functions. The variations on the theme of a β-sheet topped by two semiparallel α-helices are discussed in this review, highlighting the fantastic adaptability of this fold for good and for bad.
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Affiliation(s)
- Erin J Adams
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA.
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Lester HA, Miwa JM, Srinivasan R. Psychiatric drugs bind to classical targets within early exocytotic pathways: therapeutic effects. Biol Psychiatry 2012; 72:907-15. [PMID: 22771239 PMCID: PMC6167061 DOI: 10.1016/j.biopsych.2012.05.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 04/23/2012] [Accepted: 05/21/2012] [Indexed: 11/17/2022]
Abstract
The classical targets for antipsychotic and antidepressant drugs are G protein-coupled receptors and neurotransmitter transporters, respectively. Full therapeutic actions of these drugs require several weeks. We show how therapeutic effects may eventually accrue after existing therapeutic ligands bind to these classical targets, not on the plasma membrane but rather within endoplasmic reticulum (ER) and cis-Golgi. Consequences of such binding may include pharmacological chaperoning: the nascent drug targets are stabilized against degradation and can therefore exit the ER more readily. Another effect may be matchmaking: heterodimers and homodimers of the target form and can more readily exit the ER. Summarizing recent data for nicotinic receptors, we explain how such effects could lead to reduced ER stress and to a decreased unfolded protein response, including changes in gene activation and protein synthesis. In effects not directly related to cellular stress, escorting would allow increased ER exit and trafficking of known associated proteins, as well as other proteins such as growth factors and their receptors, producing both cell-autonomous and non-cell-autonomous effects. Axonal transport of relevant proteins may underlie the several weeks required for full therapy. In contrast, the antidepressant effects of ketamine and other N-methyl-D-aspartate receptor ligands, which occur within <2 hours, could arise from dendritically localized intracellular binding, followed by chaperoning, matchmaking, escorting, and reduced ER stress. Thus, the effects of intracellular binding extend beyond proteostasis of the targets themselves and involve pathways distinct from ion channel and G protein activation. We propose experimental tests and note pathophysiological correlates.
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Affiliation(s)
- Henry A Lester
- Division of Biology, California Institute of Technology, Pasadena, California.
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Abstract
The unfolded protein response (UPR) is a network of intracellular signaling pathways that maintain the protein-folding capacity of the endoplasmic reticulum (ER) in eukaryotic cells. Dedicated molecular sensors embedded in the ER membrane detect incompletely folded or unfolded proteins in the ER lumen and activate a transcriptional program that increases the abundance of the ER according to need. In metazoans the UPR additionally regulates translation and thus relieves unfolded protein load by globally reducing protein synthesis. If homeostasis in the ER cannot be reestablished, the metazoan UPR switches from the prosurvival to the apoptotic mode. The UPR involves a complex, coordinated action of many genes that is controlled by one ER-embedded sensor, Ire1, in yeasts, and three sensors, Ire1, PERK, and ATF6, in higher eukaryotes, including human. We discuss the emerging molecular understanding of the UPR and focus on the structural biology of Ire1 and PERK, the two recently crystallized UPR sensors.
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Affiliation(s)
- Alexei Korennykh
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
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Deng XH, Ai WM, Lei DL, Luo XG, Yan XX, Li Z. Lipopolysaccharide induces paired immunoglobulin-like receptor B (PirB) expression, synaptic alteration, and learning-memory deficit in rats. Neuroscience 2012; 209:161-70. [PMID: 22395112 DOI: 10.1016/j.neuroscience.2012.02.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 01/26/2012] [Accepted: 02/10/2012] [Indexed: 11/19/2022]
Abstract
Some typical immune proteins are expressed in the nervous system, among which the paired-immunoglobulin-like receptor B (PirB) is a receptor for major histocompatibility complex class I antigen (MHC-I), but may play a physiological role in the brain for neuronal circuitry stability by inhibiting synaptic plasticity. Chronic neuroinflammation is common to many neurodegenerative diseases and is often associated with neuronal/synaptic damage and dysfunction. Here we examined the expression of PirB in the rat brain following intracerebral application of lipopolysaccharide (LPS), which has been shown to induce proinflammatory changes and cognitive deficits in rodents. One month after unilateral intrahippocampal LPS injection (10 μg in 4 μl phosphate-buffered saline, PBS), increased protein levels and immunoreactivity of PirB were detected in the ipsilateral hippocampal formation and cortex of the experimental group relative to vehicle (PBS) control. The increased PirB labeling was localized to astrocytes and neurons. Reduced synaptophysin protein levels and immunoreactivity were also found in the ipsilateral hippocampal formation and cortex in LPS-treated rats relative to controls. Morris water maze tests indicated that hippocampus-dependent spatial learning and memory were impaired in LPS-treated animals. Our findings add new experimental data for an upregulation of immune proteins in neuronal and glial cells in the brain in a model of endotoxin-induced neuroinflammation, synaptic alteration, and cognitive decline. The results suggest that PirB modulation may be involved in the pathological process under neurodegenerative conditions.
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Affiliation(s)
- X-H Deng
- Department of Anatomy and Neurobiology, Central South University, Xiangya School of Medicine, Changsha, Hunan 410013, PR China
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Shirvani H, Gätà G, Marullo S. Regulated GPCR trafficking to the plasma membrane: general issues and the CCR5 chemokine receptor example. Subcell Biochem 2012; 63:97-111. [PMID: 23161135 DOI: 10.1007/978-94-007-4765-4_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The regulated export of nascent G protein coupled receptors (GPCRs) from intracellular stores is an emerging concept with important implications in cell biology and pharmacology. This phenomenon requires a complex network of interactions between GPCRs with either chaperones and escort proteins or gatekeepers, which are respectively involved in the progression of GPCRs along the biosynthetic pathway to the plasma membrane or in their retention in intracellular compartments. The regulated export of GPCRs is also controlled by external stimuli and might represent an adaptive mechanism to specific physiological constraints, such as the sustained activation of the CCR5 chemokine receptor in the context of chemotaxis.
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Affiliation(s)
- Hamasseh Shirvani
- Institut Cochin, Université Paris Descartes, CNRS (UMR8104), 27 rue du Fg. St. Jacques, 75014, Paris, France
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de Almeida DE, Ling S, Holoshitz J. New insights into the functional role of the rheumatoid arthritis shared epitope. FEBS Lett 2011; 585:3619-26. [PMID: 21420962 DOI: 10.1016/j.febslet.2011.03.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 12/23/2022]
Abstract
The shared epitope (SE) - an HLA-DRB1-encoded 5-amino acid sequence motif carried by the vast majority of rheumatoid arthritis (RA) patients - is a risk factor for severe disease. The mechanistic basis of RA-SE association is unknown. This group has previously demonstrated that the SE acts as a signal transduction ligand that activates nitric oxide and reactive oxygen species production. SE-activated signaling depends on cell surface calreticulin, a known innate immunity receptor previously implicated in immune regulation, autoimmunity and angiogenesis. Recent evidence that the SE enhances the polarization of Th17 cells, which is a key mechanism in autoimmunity, is discussed highlighting one of several potential functional effects of the SE in RA.
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Affiliation(s)
- Denise E de Almeida
- Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109-5680, USA
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Higenell V, Ruthazer ES. Layers upon layers: MHC class I acts in the retina to influence thalamic segregation. Neuron 2010; 65:439-41. [PMID: 20188648 DOI: 10.1016/j.neuron.2010.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Recent research has introduced the major histocompatibility complex class I (MHCI) genes as unexpected players in structural and synaptic plasticity in the central nervous system. In this issue of Neuron, Xu et al. redirect current theory by providing strong evidence for the inner retina as a site of action of MHCI proteins in retinogeniculate refinement.
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Affiliation(s)
- Valerie Higenell
- Montreal Neurological Institute, McGill University, Montréal, Québec H3A 2B4, Canada
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Williams D, Devi LA. Escorts take the lead molecular chaperones as therapeutic targets. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 91:121-49. [PMID: 20691961 DOI: 10.1016/s1877-1173(10)91005-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The functional and physiological diversity of transmembrane receptors results from factors that influence the pharmacology, signaling, and trafficking of these receptors. Receptor mutations and other modifications may lead to misfolding, intracellular retention, and ineffective signaling of transmembrane receptors. The importance of such mutations is highlighted by the fact that various diseases have been linked to mutations that lead to ineffective signaling of these receptors, resulting from the retention of receptors in intracellular compartments. Studies focused on understanding the regulation of trafficking and cell surface expression of newly synthesized receptors have highlighted molecular chaperones as key regulators of receptor maturation and sorting. In this chapter, we discuss the functions of molecular chaperones in the regulation of seven-transmembrane-containing G-protein-coupled receptor function and trafficking and explore ways in which chaperones can serve as novel therapeutic targets.
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Affiliation(s)
- Dumaine Williams
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, USA
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Abstract
The mammalian olfactory system senses an almost unlimited number of chemical stimuli and initiates a process of neural recognition that influences nearly every aspect of life. This review examines the organizational principles underlying the recognition of olfactory stimuli. The olfactory system is composed of a number of distinct subsystems that can be distinguished by the location of their sensory neurons in the nasal cavity, the receptors they use to detect chemosensory stimuli, the signaling mechanisms they employ to transduce those stimuli, and their axonal projections to specific regions of the olfactory forebrain. An integrative approach that includes gene targeting methods, optical and electrophysiological recording, and behavioral analysis has helped to elucidate the functional significance of this subsystem organization for the sense of smell.
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Affiliation(s)
- Steven D Munger
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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An escort for GPCRs: implications for regulation of receptor density at the cell surface. Trends Pharmacol Sci 2008; 29:528-35. [DOI: 10.1016/j.tips.2008.07.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 07/21/2008] [Accepted: 07/22/2008] [Indexed: 12/23/2022]
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Lambracht-Washington D, Moore YF, Wonigeit K, Lindahl KF. Structure and expression of MHC class Ib genes of the central M region in rat and mouse: M4, M5, and M6. Immunogenetics 2008; 60:131-45. [PMID: 18324395 DOI: 10.1007/s00251-008-0282-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Accepted: 01/25/2008] [Indexed: 10/22/2022]
Abstract
The M region at the telomeric end of the murine major histocompatibility complex (MHC) contains class I genes that are highly conserved in rat and mouse. We have sequenced a cosmid clone of the LEW rat strain (RT1 haplotype) containing three class I genes, RT1.M6-1, RT1.M4, and RT1.M5. The sequences of allelic genes of the BN strain (RT1n haplotype) were obtained either from cDNAs or genomic clones. For the coding parts of the genes few differences were found between the two RT1 haplotypes. In LEW, however, only RT1.M5 and RT1.M6 have open reading frames; whereas in BN all three genes were intact. In line with the findings in BN, transcription was found for all three rat genes in several tissues from strain Sprague Dawley. Protein expression in transfectants could be demonstrated for RT1.M6-1 using the monoclonal antibody OX18. By sequencing of transcripts obtained by RT-PCR, a second, transcribed M6 gene, RT1.M6-2, was discovered, which maps next to RT1.M6-1 outside of the region covered by the cosmid. In addition, alternatively spliced forms for RT1.M5 and RT1.M6 were detected. Of the orthologous mouse genes, H2-M4, H2-M5, and H2-M6, only H2-M5 has an open reading frame. Other important differences between the corresponding parts of the M region of the two species are insertion of long LINE repeats, duplication of RT1.M6, and the inversion of RT1.M5 in the rat. This demonstrates substantial evolutionary dynamics in this region despite conservation of the class I gene sequences themselves.
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Zufall F, Leinders-Zufall T. Mammalian pheromone sensing. Curr Opin Neurobiol 2007; 17:483-9. [PMID: 17709238 DOI: 10.1016/j.conb.2007.07.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Accepted: 07/19/2007] [Indexed: 11/28/2022]
Abstract
The traditional distinction that the mammalian main olfactory system recognizes general odor molecules and the accessory (vomeronasal) system detects pheromones is no longer valid. The emerging picture is that both systems have considerable overlap in terms of the chemosignals they detect and the effects that they mediate. Recent investigations have discovered large families of pheromonal signals together with a rich variety of specific receptor systems and nasal detection pathways. Selective genetic targeting of these subsystems should help to unravel their biological role in pheromone-mediated behavioral responses.
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Affiliation(s)
- Frank Zufall
- Department of Physiology, University of Saarland School of Medicine, Kirrberger Strasse, 66421 Homburg/Saar, Germany.
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Arosa FA, Santos SG, Powis SJ. Open conformers: the hidden face of MHC-I molecules. Trends Immunol 2007; 28:115-23. [PMID: 17261379 DOI: 10.1016/j.it.2007.01.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 12/13/2006] [Accepted: 01/17/2007] [Indexed: 10/23/2022]
Abstract
A pool of MHC-I molecules present at the plasma membrane can dissociate from the peptide and/or the light chain, becoming open MHC-I conformers. Whereas peptide-bound MHC-I molecules have an important role in regulating adaptive and innate immune responses, through trans-interactions with T cell and NK cell receptors, the function of the open MHC-I conformers is less clear but seems to be related to their inherent ability to cis-associate, both with themselves and with other receptors. Here, we review data indicating the open MHC-I conformers as regulators of ligand-receptor interactions and discuss the biological implications for immune and non-immune cells. The likelihood that the MHC-I heavy chains have hidden functions that are determined by the amino acid sequence of the alpha1 and alpha2 domains are discussed.
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Affiliation(s)
- Fernando A Arosa
- Lymphocyte Biology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4150-180 Porto, Portugal.
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