The Experts below are selected from a list of 957 Experts worldwide ranked by ideXlab platform
Masumi Ichikawa - One of the best experts on this subject based on the ideXlab platform.
-
xenopus v1r Vomeronasal Receptor family is expressed in the main olfactory system
Chemical Senses, 2008Co-Authors: Atsuko Dateito, Yuji Mori, Masumi Ichikawa, Hiromi Ohara, Kimiko HaginoyamagishiAbstract:To date, over 100 Vomeronasal Receptor type 1 (V1R) genes have been identified in rodents. V1R is specifically expressed in the rodent Vomeronasal organ (VNO) and is thought to be responsible for pheromone reception. Recently, 21 putatively functional V1R genes were identified in the genome database of the amphibian Xenopus tropicalis. Amphibians are the first vertebrates to possess a VNO. In order to determine at which point during evolution the vertebrate V1R genes began to function in the Vomeronasal system, we analyzed the expression of all putatively functional V1R genes in Xenopus olfactory organs. We found that V1R expression was not detected in the VNO but was specifically detected in the main olfactory epithelium (MOE). We also observed that V1R-expressing cells in the MOE coexpressed Gi2, thus suggesting that the V1R-Gi2–mediated signal transduction pathway, which is considered to play an important role in pheromone reception in the rodent VNO, exists in the amphibian MOE. These results suggest that V1R-mediated signal transduction pathway functions in Xenopus main olfactory system.
-
localization of g protein alpha subunits and morphology of Receptor neurons in olfactory and Vomeronasal epithelia in reeve s turtle geoclemys reevesii
Zoological Science, 2008Co-Authors: Yoshihiro Wakabayashi, Masumi IchikawaAbstract:Abstract Most vertebrates have two nasal epithelia: the olfactory epithelium (OE) and the Vomeronasal epithelium (VNE). The apical surfaces of OE and VNE are covered with cilia and microvilli, respectively. In rodents, signal transduction pathways involve Gαolf and Gαi2/Gαo in OE and VNE, respectively. Reeve's turtles (Geoclemys reevesii) live in a semiaquatic environment. The aim of this study was to investigate the localization of G proteins and the morphological characteristics of OE and VNE in Reeve's turtle. In-situ hybridization analysis revealed that both Gαolf and Gαo are expressed in olfactory Receptor neurons (ORNs) and Vomeronasal Receptor neurons (VRNs). Immunocytochemistry of Gαolf/s and Gαo revealed that these two G proteins were located at the apical surface, cell bodies, and axon bundles in ORNs and VRNs. Electron microscopic analysis revealed that ORNs had both cilia and microvilli on the apical surface of the same neuron, whereas VRNs had only microvilli. Moreover Gαolf/s was located on ...
-
expression of a Vomeronasal Receptor gene v1r and g protein α subunits in goat capra hircus olfactory Receptor neurons
The Journal of Comparative Neurology, 2007Co-Authors: Yoshihiro Wakabayashi, Satoshi Ohkura, Hiroaki Okamura, Yuji Mori, Masumi IchikawaAbstract:Most mammals have two distinct olfactory epithelia, the olfactory epithelium (OE) and Vomeronasal epithelium (VNE), containing, respectively, olfactory Receptor neurons (ORNs) and Vomeronasal Receptor neurons (VRNs). Olfactory Receptors (ORs), which couple to Gαolf, are generally expressed by ORNs, whereas two Vomeronasal Receptor families (V1rs and V2rs) coupled respectively to Gαi2 and Gαo, are expressed by VRNs. Previously, we reported that one goat V1rs (gV1ra1) is expressed by ORNs and VRNs. To investigate the characteristics of Vomeronasal-Receptor-expressing ORNs in mammals we performed double-label in situ hybridization for gV1ra1, Gαi2, Gαolf, olfactory marker protein (OMP), and growth association protein 43 (GAP43). Goat V1r-expressing ORNs are categorized into two types situated in different areas of the epithelium. The first type of V1r-expressing ORN coexpressed Gαi2, but not OMP or GAP43. The second type of V1r-expressing ORN expresses Gαolf and OMP, but not Gαi2 or GAP43. These findings suggest that the two types of V1r-expressing ORN in goat OE function using different G protein α subunits for chemoreception. J. Comp. Neurol. 503:371–380, 2007. © 2007 Wiley-Liss, Inc.
-
stable knock down of Vomeronasal Receptor genes in transgenic xenopus tadpoles
Biochemical and Biophysical Research Communications, 2006Co-Authors: Akihiko Kashiwagi, Shouichiro Saito, Masumi Ichikawa, Yuji Mori, Atsuko Dateito, Keiko Kashiwagi, Kimiko HaginoyamagishiAbstract:Xenopus V2R (xV2R), a family of G-protein-coupled Receptors with seven transmembrane domains, is expressed in the Xenopus Vomeronasal organ (VNO). There are six subgroups of xV2R, one of which, xV2RE, is predominantly expressed in the VNO. To understand the function of xV2R during VNO development, we developed a new method to achieve stable siRNA-suppression of the V2RE genes by introducing siRNA expression transgenes into the genomes of unfertilized eggs. We found that some of the derived transgenic tadpoles lacked VNOs and that their olfactory epithelium was fused. With the exception of one tadpole, expression of xV2RE was not detected in morphologically abnormal mutant tadpoles, although the olfactory marker protein and the olfactory Receptors were expressed. These results suggest that we successfully produced transgenic tadpoles in which xV2RE expression was stably suppressed by siRNA, and that xV2RE plays a role in the morphogenesis of olfactory organs.
-
maturation of Vomeronasal Receptor neurons in vitro by coculture with accessory olfactory bulb neurons
Chemical Senses, 2005Co-Authors: Keiko Moriyaito, Toshiya Osada, Yuuki Ishimatsu, Kazuyo Muramoto, Testuyuki Kobayashi, Masumi IchikawaAbstract:To analyze the mechanisms of perception and processing of pheromonal signals in vitro, we previously developed a new culture system for Vomeronasal Receptor neurons (VRNs), referred to as the Vomeronasal pocket (VN pocket). However, very few VRNs were found to express the olfactory marker protein (OMP) and to have protruding microvilli in VN pockets, indicating that these VRNs are immature and that VN pockets are not appropriate for pheromonal recognition. To induce VRN maturation in VN pockets, we here attempted to coculture VN pockets with a VRN target—accessory olfactory bulb (AOB) neurons. At 3 weeks of coculture with AOB neurons, the number of OMP-immunopositive VRNs increased. By electron microscopy, the development of microvilli in VRNs was found to occur coincidentally with OMP expression in vitro. These results indicate that VRN maturation is induced by coculture with AOB neurons. The OMP expression of VRNs was induced not only by AOB neurons but also by neurons of other parts of the central nervous system (CNS). Thus, VRN maturation requires only CNS neurons. Since the maturation of VRNs was not induced in one-well separate cultures, the nonspecific induction of OMP expression by CNS neurons suggests the involvement of a direct contact effect with CNS in VRN maturation.
Peter Mombaerts - One of the best experts on this subject based on the ideXlab platform.
-
subpopulations of Vomeronasal sensory neurons with coordinated coexpression of type 2 Vomeronasal Receptor genes are differentially dependent on vmn2r1
European Journal of Neuroscience, 2018Co-Authors: Sachiko Akiyoshi, Tomohiro Ishii, Peter MombaertsAbstract:The mouse Vomeronasal organ is specialized in the detection of pheromones. Vomeronasal sensory neurons (VSNs) express chemosensory Receptors of two large gene repertoires, V1R and V2R, which encode G-protein-coupled Receptors. Phylogenetically, four families of V2R genes can be discerned as follows: A, B, C, and D. VSNs located in the basal layer of the Vomeronasal epithelium coordinately coexpress V2R genes from two families: Approximately half of basal VSNs coexpress Vmn2r1 of family C with a single V2R gene of family A8-10, B, or D ('C1 type of V2Rs'), and the other half coexpress Vmn2r2 through Vmn2r7 of family C with a single V2R gene of family A1-6 ('C2 type V2Rs'). The regulatory mechanisms of the coordinated coexpression of V2Rs from two families remain poorly understood. Here, we have generated two mouse strains carrying a knockout mutation in Vmn2r1 by gene targeting in embryonic stem cells. These mutations cause a differential decrease in the numbers of VSNs expressing a given C1 type of V2R. There is no compensatory expression of Vmn2r2 through Vmn2r7. VSN axons coalesce into glomeruli in the appropriate region of the accessory olfactory bulb in the absence of Vmn2r1. Gene expression profiling by NanoString reveals a differential and graded decrease in the expression levels across C1 type of V2Rs. There is no change in the expression levels of C2 type of V2Rs, with two exceptions that we reclassified as C1 type. Thus, there appears to be a fixed probability of gene choice for a given C2 type of V2R.
-
coordinated coexpression of two Vomeronasal Receptor v2r genes per neuron in the mouse
Molecular and Cellular Neuroscience, 2011Co-Authors: Tomohiro Ishii, Peter MombaertsAbstract:Abstract The detection of chemosensory stimuli by the sensory neurons of the mouse Vomeronasal organ (VNO) is mainly mediated by seven-transmembrane Receptors that are encoded by two large gene repertoires, V1R and V2R. The mouse genome contains 122 intact V2R genes, which can be grouped in four families by sequence homology: families A, B, and D (115 genes), and family C (7 genes). Vomeronasal sensory neurons (VSNs) in the basal layer of the VNO epithelium coexpress two V2R genes in non-random combinations: one family-ABD V2R gene together with one family-C V2R gene, such as Vmn2r1 (29% of basal VSNs) or Vmn2r2 (52%). This coordinated coexpression may contribute to the highly specialized sensory response profiles of VSNs, for instance by heterodimerization of a family-ABD with a family-C V2R. The mechanisms that regulate this coordinated cooexpression of two V2R genes per basal VSN are not understood. Among possible models are a sequential and dependent model of expression; a model of random combinations of expression followed by cellular selection of VSNs with appropriate combinations; and a model of direct coordination of gene expression by another gene family such as genes encoding transcription factors. Here, we describe two novel mouse strains with targeted mutations in the family-ABD V2R gene V2rf2 that begin to provide insight into this problem. We observe that the great majority of VSNs that express intact V2rf2 coexpress Vmn2r1 immunoreactivity, and that the percentage of Vmn2r1 coexpression increases from 3 to 10 wk. Having established this tight coexpression of V2rf2 with Vmn2r1, we then asked if it is maintained when the coding sequence of V2rf2 is deleted. We find that the number of VSNs expressing a locus with a targeted deletion in the coding sequence of V2rf2 that is likely a null mutation, is similar to the number of VSNs that express intact V2rf2. But 25% of these VSNs coexpress another family-ABD V2R, which is consistent with the absence of negative feedback from the mutated V2rf2 locus. Interestingly, 9.5% of VSNs expressing the targeted deletion of V2rf2 now coexpress Vmn2r2. Finally, the marginal region of the VNO epithelium, where immature VSNs are concentrated, has more RNA of family-ABD V2R genes than of family-C genes in postnatal wild-type mice. Our results are most consistent with the sequential and dependent model for the coordinated coexpression of two V2R genes per basal VSN.
-
odorant and Vomeronasal Receptor genes in two mouse genome assemblies
Genomics, 2004Co-Authors: Xinmin Zhang, Ivan Rodriguez, Peter Mombaerts, Stuart FiresteinAbstract:Odorant Receptors (ORs) and Vomeronasal Receptors (V1Rs and V2Rs) are large superfamilies of chemosensory Receptors. As an extension of previous research using the 2001 Celera mouse genome assembly, we analyzed OR and V1R genes in the 2002 public mouse genome assembly. We identified 1403 OR genes (1068 potentially intact) and 332 V1R genes (164 potentially intact) in this C57BL/6J mouse genome. This expands the mouse OR and V1R superfamilies by adding approximately 100 OR and approximately 40 V1R potentially intact genes. The description of the genomic distribution of OR genes is more complete and accurate, and two major errors in OR gene distribution in the 2001 Celera assembly were corrected. For the first time, the complete genomic distribution of V1R genes was investigated in detail and placed in context with that of OR genes. V1R genes, like OR genes, tend to form clusters of similar genes in the genome. Comparison between the two genome assemblies revealed a high rate of single-nucleotide polymorphisms (SNPs) in both OR and V1R genes. The high ratio of nonsynonymous SNPs over synonymous SNPs in V1R genes suggests positive selection for these genes, possibly favoring species-specific and strain-specific pheromone detection. In addition, detailed analysis of the SNP rate aided in the identification of key residues in ORs.
-
deficient pheromone responses in mice lacking a cluster of Vomeronasal Receptor genes
Nature, 2002Co-Authors: Karina Del Punta, Frank Zufall, Ivan Rodriguez, Trese Leinderszufall, David Jukam, Charles J Wysocki, Sonoko Ogawa, Peter MombaertsAbstract:The mammalian Vomeronasal organ (VNO), a part of the olfactory system, detects pheromones—chemical signals that modulate social and reproductive behaviours1,2. But the molecular Receptors in the VNO that detect these chemosensory stimuli remain undefined. Candidate pheromone Receptors are encoded by two distinct and complex superfamilies of genes, V1r and V2r (refs 3 and 4), which code for Receptors with seven transmembrane domains. These genes are selectively expressed in sensory neurons of the VNO. However, there is at present no functional evidence for a role of these genes in pheromone responses. Here, using chromosome engineering technology5, we delete in the germ line of mice a ∼600-kilobase genomic region that contains a cluster of 16 intact V1r genes6. These genes comprise two of the 12 described V1r gene families7, and represent ∼12% of the V1r repertoire. The mutant mice display deficits in a subset of VNO-dependent behaviours: the expression of male sexual behaviour and maternal aggression is substantially altered. Electrophysiologically, the epithelium of the VNO of such mice does not respond detectably to specific pheromonal ligands. The behavioural impairment and chemosensory deficit support a role of V1r Receptors as pheromone Receptors.
-
Multiple new and isolated families within the mouse superfamily of V1r Vomeronasal Receptors.
Nature Neuroscience, 2002Co-Authors: Ivan Rodriguez, Karina Del Punta, Andrea Rothman, Tomohiro Ishii, Peter MombaertsAbstract:Seven-transmembrane-domain proteins encoded by the Vomeronasal Receptor V1r and V2r gene superfamilies, and expressed by Vomeronasal sensory neurons, are believed to be pheromone Receptors in rodents. Four V1r gene families have been described in the mouse (V1ra, V1rb, V1rc and V3r). Here we have screened near-complete mouse genomic databases to obtain a first global draft of the mouse V1r repertoire, including 104 new V1r genes. It comprises eight new and extremely isolated families in addition to the four families previously identified. Members of these new families were expressed in Vomeronasal sensory neurons. The genome-wide view revealed great sequence diversity within the V1r superfamily. Phylogenetic analyses suggested an ancient original radiation, followed by the isolation, divergence and expansion of families by extensive gene duplications and frequent gene loss. The isolated nature of these gene families probably reflects a specialization of different Receptor classes in the detection of specific types of chemicals.
Kimiko Haginoyamagishi - One of the best experts on this subject based on the ideXlab platform.
-
evolution of Vomeronasal Receptor 1 v1r genes in the common marmoset callithrix jacchus
Gene, 2018Co-Authors: Keiko Moriyaito, Kimiko Haginoyamagishi, Takashi Hayakawa, Hikoyu Suzuki, Masato NikaidoAbstract:Abstract Pheromones are crucial for eliciting innate responses and inducing social and sexual behaviors in mammals. The Vomeronasal Receptor 1 genes, V1Rs, encode members of a pheromone Receptor family that are mainly expressed in the Vomeronasal organ (VNO). The V1R family shows extraordinary variety in gene number among vertebrates owing to successive gene gains and losses during evolution. Such diversity is believed to reflect a degree of dependence on the VNO. We investigated V1R evolution in primate lineages closely related to humans because these VNOs show a trend toward degeneration. We performed extensive phylogenetic analyses for V1Rs from a broad range of primate species. Although the decline of intact genes was evident in anthropoids (hominoids, Old World monkeys and New World monkeys), we found that a certain number of intact genes persist in New World monkeys. In one New World monkey species, the common marmoset (Callithrix jacchus), we examined seven putatively functional V1Rs using in situ hybridization and reverse transcription-PCR. Based on their mRNA expression patterns in the VNO and other organs, two types of V1Rs emerged: the canonical class with VNO-specific expression, and a second group having more ubiquitous expression in various organs as well as VNO. Furthermore, phylogenetic analysis revealed that the class with the more widespread expression had been retained longer in evolution than the VNO-specific type. We propose that the acquisition of a novel non-VNO–related function(s) may have led to the survival of a small but persistent number of V1Rs in anthropoid primates.
-
accessory olfactory bulb neurons are required for maintenance but not induction of v2r Vomeronasal Receptor gene expression in vitro
Neuroscience Letters, 2011Co-Authors: Kazuyo Muramoto, Kimiko Haginoyamagishi, Keiichi Tonosaki, Hideto KabaAbstract:Abstract Many mammals detect pheromones by a sensory organ, the Vomeronasal organ (VNO). In a previous study using immunoblot and immunocytochemical analyses, we reported that cocultures of VNOs with accessory olfactory bulb (AOB) neurons resulted in the maturation of Vomeronasal sensory neurons (VSNs) and a greater expression of V2R family Vomeronasal Receptors than cultures with VNO alone. To further characterize the V2R expression, we here investigated the time course of the expression of V2R mRNA in the presence or absence of AOB neurons using RT-PCR analysis. The expression of V2R mRNA was already detectable not only in the VNO cocultured with AOB neurons for 3 days in coculture but also in the VNO cultured alone for the same number of days. However, the expression of V2R mRNA in the VNO cultured alone was remarkably decreased during the additional culture period, although that in the cocultured VNO showed sustained expression. Moreover, the application of 2 μM TTX to the cocultured VNO resulted in a marked decrease in the V2R mRNA expression to a level equal to that in the VNO cultured alone for 14 days in coculture. Our previous working hypothesis was that the expression of V2Rs in VSNs was induced by interacting with AOB neurons. However, the present results suggest that the Receptor expression in VSNs is independent of the interaction with AOB neurons in the early developmental stage, but is maintained by the active interaction with AOB neurons.
-
xenopus v1r Vomeronasal Receptor family is expressed in the main olfactory system
Chemical Senses, 2008Co-Authors: Atsuko Dateito, Yuji Mori, Masumi Ichikawa, Hiromi Ohara, Kimiko HaginoyamagishiAbstract:To date, over 100 Vomeronasal Receptor type 1 (V1R) genes have been identified in rodents. V1R is specifically expressed in the rodent Vomeronasal organ (VNO) and is thought to be responsible for pheromone reception. Recently, 21 putatively functional V1R genes were identified in the genome database of the amphibian Xenopus tropicalis. Amphibians are the first vertebrates to possess a VNO. In order to determine at which point during evolution the vertebrate V1R genes began to function in the Vomeronasal system, we analyzed the expression of all putatively functional V1R genes in Xenopus olfactory organs. We found that V1R expression was not detected in the VNO but was specifically detected in the main olfactory epithelium (MOE). We also observed that V1R-expressing cells in the MOE coexpressed Gi2, thus suggesting that the V1R-Gi2–mediated signal transduction pathway, which is considered to play an important role in pheromone reception in the rodent VNO, exists in the amphibian MOE. These results suggest that V1R-mediated signal transduction pathway functions in Xenopus main olfactory system.
-
stable knock down of Vomeronasal Receptor genes in transgenic xenopus tadpoles
Biochemical and Biophysical Research Communications, 2006Co-Authors: Akihiko Kashiwagi, Shouichiro Saito, Masumi Ichikawa, Yuji Mori, Atsuko Dateito, Keiko Kashiwagi, Kimiko HaginoyamagishiAbstract:Xenopus V2R (xV2R), a family of G-protein-coupled Receptors with seven transmembrane domains, is expressed in the Xenopus Vomeronasal organ (VNO). There are six subgroups of xV2R, one of which, xV2RE, is predominantly expressed in the VNO. To understand the function of xV2R during VNO development, we developed a new method to achieve stable siRNA-suppression of the V2RE genes by introducing siRNA expression transgenes into the genomes of unfertilized eggs. We found that some of the derived transgenic tadpoles lacked VNOs and that their olfactory epithelium was fused. With the exception of one tadpole, expression of xV2RE was not detected in morphologically abnormal mutant tadpoles, although the olfactory marker protein and the olfactory Receptors were expressed. These results suggest that we successfully produced transgenic tadpoles in which xV2RE expression was stably suppressed by siRNA, and that xV2RE plays a role in the morphogenesis of olfactory organs.
-
expression of Vomeronasal Receptor genes in xenopus laevis
The Journal of Comparative Neurology, 2004Co-Authors: Kimiko Haginoyamagishi, Keiko Moriya, Hideo Kubo, Yoshihiro Wakabayashi, Naoko Isobe, Shouichiro Saito, Masumi Ichikawa, Kazumori YazakiAbstract:In the course of evolution, the Vomeronasal organ (VNO) first appeared in amphibians. To understand the relationship between the VNO and the Vomeronasal Receptors, we isolated and analyzed the expression of the Vomeronasal Receptor genes of Xenopus laevis. We identified genes of the Xenopus V2R Receptor family, which are predominantly expressed throughout the sensory epithelium of the VNO. The G-protein Go, which is coexpressed with V2Rs in the rodent VNO, was also extensively expressed throughout the Vomeronasal sensory epithelium. These results strongly suggest that the V2Rs and Go are coexpressed in the Vomeronasal Receptor cells. The predominant expression of the Xenopus V2R families and the coexpression of the V2Rs and Go imply that V2Rs play important roles in the sensory transduction of Xenopus VNO. We found that these Receptors were expressed not only in the VNO, but also in the posterolateral epithelial area of the principal cavity (PLPC). Electron microscopic study revealed that the epithelium of the PLPC is more like that of the VNO than that of the principal and the middle cavity. These results suggest that in adult Xenopus the V2Rs analyzed so far are predominantly expressed in the Vomeronasal and Vomeronasal-like epithelium. The analysis of V2R expression in Xenopus larvae demonstrates that V2Rs are predominantly expressed in the VNO even before metamorphosis. J. Comp. Neurol. 472:246–256, 2004. © 2004 Wiley-Liss, Inc.
Jianzhi Zhang - One of the best experts on this subject based on the ideXlab platform.
-
the microevolution of v1r Vomeronasal Receptor genes in mice
Genome Biology and Evolution, 2011Co-Authors: Seong Hwan Park, Ondrej Podlaha, Wendy E Grus, Jianzhi ZhangAbstract:: Vomeronasal sensitivity is important for detecting intraspecific pheromonal cues as well as environmental odorants and is involved in mating, social interaction, and other daily activities of many vertebrates. Two large families of seven-transmembrane G-protein-coupled Receptors, V1rs and V2rs, bind to various ligands to initiate Vomeronasal signal transduction. Although the macroevolution of V1r and V2r genes has been well characterized throughout vertebrates, especially mammals, little is known about their microevolutionary patterns, which hampers a clear understanding of the evolutionary forces behind the rapid evolutionary turnover of V1r and V2r genes and the great diversity in Receptor repertoire across species. Furthermore, the role of divergent Vomeronasal perception in enhancing premating isolation and maintaining species identity has not been evaluated. Here we sequenced 44 V1r genes and 25 presumably neutral noncoding regions in 14 wild-caught mice belonging to Mus musculus and M. domesticus, two closely related species with strong yet incomplete reproductive isolation. We found that nucleotide changes in V1rs are generally under weak purifying selection and that only ∼5% of V1rs may have been subject to positive selection that promotes nonsynonymous substitutions. Consistent with the low functional constraints on V1rs, 18 of the 44 V1rs have null alleles segregating in one or both species. Together, our results demonstrate that, despite occasional actions of positive selection, the evolution of V1rs is in a large part shaped by purifying selection and random drift. These findings have broad implications for understanding the driving forces of rapid gene turnovers that are often observed in the evolution of large gene families.
-
comparative genomic analysis identifies an evolutionary shift of Vomeronasal Receptor gene repertoires in the vertebrate transition from water to land
Genome Research, 2007Co-Authors: Jianzhi ZhangAbstract:Two evolutionarily unrelated superfamilies of G-protein coupled Receptors, V1Rs and V2Rs, bind pheromones and “ordinary” odorants to initiate Vomeronasal chemical senses in vertebrates, which play important roles in many aspects of an organism’s daily life such as mating, territoriality, and foraging. To study the macroevolution of Vomeronasal sensitivity, we identified all V1R and V2R genes from the genome sequences of 11 vertebrates. Our analysis suggests the presence of multiple V1R and V2R genes in the common ancestor of teleost fish and tetrapods and reveals an exceptionally large among-species variation in the sizes of these gene repertoires. Interestingly, the ratio of the number of intact V1R genes to that of V2R genes increased by ∼50-fold as land vertebrates evolved from aquatic vertebrates. A similar increase was found for the ratio of the number of class II odorant Receptor (OR) genes to that of class I genes, but not in other vertebrate gene families. Because V1Rs and class II ORs have been suggested to bind to small airborne chemicals, whereas V2Rs and class I ORs recognize water-soluble molecules, these increases reflect a rare case of adaptation to terrestrial life at the gene family level. Several gene families known to function in concert with V2Rs in the mouse are absent outside rodents, indicating rapid changes of interactions between Vomeronasal Receptors and their molecular partners. Taken together, our results demonstrate the exceptional evolutionary fluidity of Vomeronasal Receptors, making them excellent targets for studying the molecular basis of physiological and behavioral diversity and adaptation.
-
composition and evolution of the v2r Vomeronasal Receptor gene repertoire in mice and rats
Genomics, 2005Co-Authors: Hui Yang, Yaping Zhang, Jianzhi ZhangAbstract:Pheromones are chemicals produced and detected by conspecifics to elicit social/sexual physiological and behavioral responses, and they are perceived primarily by the Vomeronasal organ (VNO) in terrestrial vertebrates. Two large superfamilies of G protein-coupled Receptors, V1rs and V2rs, have been identified as pheromone Receptors in Vomeronasal sensory neurons. Based on a computational analysis of the mouse and rat genome sequences, we report the first global draft of the V2r gene repertoire, composed of ¨200 genes and pseudogenes. Rodent V2rs are subject to rapid gene births/deaths and accelerated amino acid substitutions, likely reflecting the species-specific nature of pheromones. Vertebrate V2rs appear to have originated twice prior to the emergence of the VNO in ancestral tetrapods, explaining seemingly inconsistent observations among different V2rs. The identification of the entire V2r repertoire opens the door to genomic-level studies of the structure, function, and evolution of this diverse group of sensory Receptors.
Kenzo Kurihara - One of the best experts on this subject based on the ideXlab platform.
-
inositol 1 4 5 trisphosphate induces responses in Receptor neurons in rat Vomeronasal sensory slices
Chemical Senses, 1997Co-Authors: Kouhei Inamura, Makoto Kashiwayanagi, Kenzo KuriharaAbstract:: Using the whole-cell mode of the patch-clamp technique, we recorded action potentials, voltage-activated cationic currents and putative second messenger-activated currents in Receptor neurons in the Vomeronasal sensory epithelium of female rats. The resting membrane potential and input resistance were -45.5 +/- 2.5 mV (mean +/- SEM, n = 39) and 1.5 +/- 0.2 G omega (mean +/- SEM, n = 37). Current injection of 1-3 pA induced overshooting action potentials. The firing frequency increased with increasing current injections linearly from 1 to 10 pA and reached a plateau at 30 pA, suggesting that rat Vomeronasal Receptor neurons sensitively elicit action potentials in response to a small Receptor potential. Under voltage clamp, voltage-dependent Na+ inward current, inward Ca2+ current, sustained outward K+ current and Ca-(2+)-activated K(+)-current were identified. Dialysis of D-inositol-1,4,5-trisphosphate (D-IP3) induced inward currents with an increase in membrane conductance in approximately 54% of the cells and inward current fluctuations in 15% of the cell. L-IP3 also induced inward currents and current fluctuations in 53 and 13% of the cells respectively. The mean amplitude of inward currents induced by 100 microM D-IP3 and L-IP3 were 84.6 +/- 14.0 pA (SEM, n = 82) and 66.1 +/- 9.4 pA (SEM, n = 100) respectively. The IP3-induced responses were blocked by elimination of Na+ and Ca2+ in the external solution or application of 10 microM ruthenium red. The present study suggested that IP3-mediated transduction pathways exist in rat Vomeronasal Receptor neurons.
-
intracellular dialysis of cyclic nucleotides induces inward currents in turtle Vomeronasal Receptor neurons
The Journal of Neuroscience, 1996Co-Authors: Mutsuo Taniguchi, Makoto Kashiwayanagi, Kenzo KuriharaAbstract:Turtle Vomeronasal Receptor neurons in slice preparations were studied using the patch-clamp technique in the whole-cell and cell-attached configurations. The mean resting potential was -48, and the response to an injected current step consisted of either a single spike or a train of spikes. An injected current of 3–30 pA was required to depolarize the neuron to spike threshold near -50 mV. Voltage-clamped Vomeronasal Receptor neurons displayed transient inward currents followed by sustained outward currents in response to depolarizing voltage steps. In cell-attached recordings, 10 microM forskolin added to the bath caused a transient increase of spike rate. Intracellular application of cAMP evoked ann inward current in a dose-dependent manner from the neurons voltage clamped at -70 mV; 0.1 mM cAMP was sufficient to elicit an inward current in the neurons. The magnitude of the response to cAMP reached a plateau at 1 mM with an average peak amplitude of 176 +/- 34 pA. Intracellular application of 1 mM cGMP also evoked an inward current with an average peak amplitude of 227 +/- 61 pA. The reversal potentials of the induced components were estimated to be 10 +/- 7 mV for cAMP and -4 +/- 16 mV for cGMP. The reversal potential of the cAMP- induced current in external Cl(-)-free solution was similar to that in normal Ringer9s solution, suggesting that Cl- current is not significantly involved in the current. The present results represent the first evidence of cyclic nucleotide-activated conductance in the Vomeronasal Receptor membranes.
-
intracellular injection of inositol 1 4 5 trisphosphate increases a conductance in membranes of turtle Vomeronasal Receptor neurons in the slice preparation
Neuroscience Letters, 1995Co-Authors: Mutsuo Taniguchi, Makoto Kashiwayanagi, Kenzo KuriharaAbstract:Abstract Inositol 1,4,5-trisphosphate (IP 3 ) was injected into turtle Vomeronasal Receptor neurons in the slice preparation under a whole-cell patch clamp, and the evoked current was measured. Application of 0.1 mM IP 3 evoked a prolonged, inward current (52 of 98 neurons) with an average peak amplitude of 89.9 ± 10.9 pA. The reversal potential of the response induced by IP 3 was estimated to be −32.3 ± 1.5 mV (6 neurons). Bathing the neurons in 10 μM ruthenium red solution greatly reduced the IP 3 evoked inward current to 18.0 ± 4.6 pA (5 neurons). This is the first study to demonstrate that the membranes of the turtle Vomeronasal neurons carry IP 3 -activated conductance.
