Spatial patterns of olfactory neurons expressing specific odor receptor genes in 48-hour-old embryos of zebrafish Danio rerio.

1997 ◽  
Vol 200 (3) ◽  
pp. 433-443 ◽  
Author(s):  
R G Vogt ◽  
S M Lindsay ◽  
C A Byrd ◽  
M Sun
Keyword(s):  
Spatial Patterns ◽  
Olfactory Epithelium ◽  
Expression Patterns ◽  
Initial Population ◽  
Olfactory Neuron ◽  
Olfactory Neurons ◽  
Odor Receptor ◽  
Or Gene ◽  
Or Genes ◽  
Specific Odor

Olfactory neurons have a complex phenotype characterized by their expression of a specific odor receptor (OR) gene and their targeting of an equally specific locus in the olfactory bulb. In the adult fish, olfactory neurons expressing specific ORs are broadly distributed in the epithelium, intermingling with neurons expressing other OR phenotypes. This distributed adult pattern has led to the suggestion that olfactory neuron phenotype is determined by a stochastic process, independent of external positional cues. However, when the fish olfactory system is established during embryogenesis it is simple in its organization, with few olfactory neurons and an olfactory epithelium that has not yet folded into the adult morphology. It is possible that positional cues might act in the embryo to establish an initial population and pattern of olfactory neuron phenotypes and that subsequent morphogenesis and neuronal addition lead to the randomized distribution of neurons. To test this possibility, we examined the spatial patterns of olfactory neurons expressing specific OR genes in 48 h embryos, a time of relative simplicity in the developing olfactory epithelium. Three-dimensional plots of neuron distributions were made, and comparison of OR expression patterns were made between right and left epithelia, between individual animals and between different OR genes. The patterns of OR gene expression were not conserved in these comparison. Mathematical analysis of 21 epithelia for the degree of order in the distribution of olfactory neurons argued strongly that the neurons expressing given ORs are randomly distributed in the 48 h embryos. These results are consistent with those observed from adult tissue and support models suggesting that extrinsic positional cues do not have a major role in specifying olfactory neuron phenotypes.

Mash1 activates a cascade of bHLH regulators in olfactory neuron progenitors

Development ◽  
1997 ◽  
Vol 124 (8) ◽  
pp. 1611-1621 ◽  
Author(s):  
E. Cau ◽  
G. Gradwohl ◽  
C. Fode ◽  
F. Guillemot
Keyword(s):  
Olfactory Epithelium ◽  
Early Stage ◽  
Expression Patterns ◽  
Cellular Level ◽  
Olfactory Neuron ◽  
Olfactory Neurons ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Proliferation And Differentiation ◽  
Distinct Stage

The lineage of olfactory neurons has been relatively well characterized at the cellular level, but the genes that regulate the proliferation and differentiation of their progenitors are currently unknown. In this study, we report the isolation of a novel murine gene, Math4C/neurogenin1, which is distantly related to the Drosophila proneural gene atonal. We show that Math4C/neurogenin1 and the basic helix-loop-helix gene Mash1 are expressed in the olfactory epithelium by different dividing progenitor populations, while another basic helix-loop-helix gene, NeuroD, is expressed at the onset of neuronal differentiation. These expression patterns suggest that each gene marks a distinct stage of olfactory neuron progenitor development, in the following sequence: Mash1>Math4C/neurogenin1>NeuroD. We have previously reported that inactivation of Mash1 function leads to a severe reduction in the number of olfactory neurons. We show here that most cells in the olfactory epithelium of Mash1 mutant embryos fail to express Math4C/neurogenin1 or NeuroD. Strikingly, a subset of progenitor cells in a ventrocaudal domain of Mash1 mutant olfactory epithelium still express Math4C/neurogenin1 and NeuroD and differentiate into neurons. Cells in this domain also express Math4A/neurogenin2, another member of the Math4/neurogenin gene family, and not Mash1. Our results demonstrate that Mash1 is required at an early stage in the olfactory neuron lineage to initiate a differentiation program involving Math4C/neurogenin1 and NeuroD. Another gene activates a similar program in a separate population of olfactory neuron progenitors.

scholarly journals Gene Expression and Functional Analyses of Odorant Receptors in Small Hive Beetles (Aethina tumida)

2020 ◽  
Vol 21 (13) ◽  
pp. 4582
Author(s):  
Yuanzhen Liu ◽  
Alexis Beaurepaire ◽  
Curtis W. Rogers ◽  
Dawn Lopez ◽  
Jay D. Evans ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Host Finding ◽  
Odorant Receptors ◽  
Aethina Tumida ◽  
Colony Odor ◽  
Or Gene ◽  
Functional Analyses ◽  
Or Genes ◽  
Small Hive Beetles ◽  
First Time

Olfaction is key to many insects. Odorant receptors (ORs) stand among the key chemosensory receptors mediating the detection of pheromones and kairomones. Small hive beetles (SHBs), Aethina tumida, are parasites of social bee colonies and olfactory cues are especially important for host finding. However, how interactions with their hosts may have shaped the evolution of ORs in the SHB remains poorly understood. Here, for the first time, we analyzed the evolution of SHB ORs through phylogenetic and positive selection analyses. We then tested the expression of selected OR genes in antennae, heads, and abdomens in four groups of adult SHBs: colony odor-experienced/-naive males and females. The results show that SHBs experienced both OR gene losses and duplications, thereby providing a first understanding of the evolution of SHB ORs. Additionally, three candidate ORs potentially involved in host finding and/or chemical communication were identified. Significantly different downregulations of ORs between the abdomens of male and female SHBs exposed to colony odors may reflect that these expression patterns might also reflect other internal events, e.g., oviposition. Altogether, these results provide novel insights into the evolution of SHB ORs and provide a valuable resource for analyzing the function of key genes, e.g., for developing biological control. These results will also help in understanding the chemosensory system in SHBs and other beetles.

scholarly journals Homeotic Regulation of Olfactory Receptor Choice via NFI-dependent Heterochromatic Silencing and Genomic Compartmentalization

2020 ◽  
Author(s):  
Elizaveta Bashkirova ◽  
Kevin Monahan ◽  
Christine E. Campbell ◽  
Jason M. Osinski ◽  
Longzhi Tan ◽  
...  
Keyword(s):  
Long Range ◽  
Olfactory Epithelium ◽  
Chromatin Structure ◽  
Olfactory Receptor ◽  
Genome Architecture ◽  
Olfactory Neuron ◽  
Dorsoventral Axis ◽  
Heterochromatin Formation ◽  
Or Genes ◽  
Ventral Zones

AbstractExpression of one out of >1000 olfactory receptor (OR) genes is stochastic but, yet, spatially organized in stereotypic anatomical segments, or “zones”, along the dorsoventral axis of the mouse olfactory epithelium. We discovered that zonal OR expression is specified by OR chromatin structure and genome architecture during olfactory neuron differentiation. Specifically, across every zone dorsally expressed ORs have higher levels of heterochromatic marks and long-range contacts than ORs expressed ventrally. However, OR heterochromatin levels and frequency of genomic contacts between ORs gradually increase towards ventral zones. Consequently, ORs from dorsal indexes accumulate high H3K9me3/H3K79me3 enrichment and become silenced in ventral zones, while ORs from ventral indexes lack activating long-range genomic interactions and, thus, cannot be chosen in dorsal segments. This process is regulated by NFIA, B, and X gradients along the dorsoventral axis, triple deletion of which causes homeotic transformations on zonal OR expression, heterochromatin formation, and genomic compartmentalization.

scholarly journals Olfactory receptor subgenome and expression in a highly olfactory procellariiform seabird

Genetics ◽  
2021 ◽  
Author(s):  
Simon Yung Wa Sin ◽  
Alison Cloutier ◽  
Gabrielle Nevitt ◽  
Scott V Edwards
Keyword(s):  
Olfactory Receptor ◽  
Copy Number ◽  
Expression Patterns ◽  
Bird Species ◽  
Differentially Expressed ◽  
Valuable Insight ◽  
Counting Method ◽  
Age Classes ◽  
Or Gene ◽  
Or Genes

Abstract Procellariiform seabirds rely on their sense of smell for foraging and homing. Both genomes and transcriptomes yield important clues about how olfactory receptor (OR) subgenomes are shaped by natural and sexual selection, yet no transcriptomes have been made of any olfactory epithelium of any bird species thus far. Here we assembled a high-quality genome and nasal epithelium transcriptome of the Leach’s storm-petrel (Oceanodroma leucorhoa) to extensively characterize their OR repertoire. Using a depth-of-coverage-assisted counting method, we estimated over 160 intact OR genes (∼500 including OR fragments). This method reveals the highest number of intact OR genes and the lowest proportion of pseudogenes compared to other waterbirds studied, and suggests that rates of OR gene duplication vary between major clades of birds, with particularly high rates in passerines. OR expression patterns reveal two OR genes (OR6-6 and OR5-11) highly expressed in adults, and four OR genes (OR14-14, OR14-12, OR10-2, and OR14-9) differentially expressed between age classes of storm-petrels. All four genes differentially expressed between age classes were more highly expressed in chicks compared to adults, suggesting that ORs genes may exhibit ontogenetic specializations. Three highly differentially expressed OR genes also had high copy number ratios, suggesting that expression variation may be linked to copy number in the genome. We provide better estimates of OR gene number by using a copy number-assisted counting method, and document ontogenetic changes in OR gene expression that may be linked to olfactory specialization. These results provide valuable insight into the expression, development, and macroevolution of olfaction in seabirds.

scholarly journals Evolutionary dynamics of the OR gene repertoire in teleost fishes: evidence of an association with changes in olfactory epithelium shape

2021 ◽  
Author(s):  
Maxime Policarpo ◽  
Katherine E Bemis ◽  
James C Tyler ◽  
Cushla J Metcalfe ◽  
Patrick Laurenti ◽  
...  
Keyword(s):  
Olfactory Epithelium ◽  
Evolutionary Dynamics ◽  
Morphological Changes ◽  
Olfactory Organ ◽  
Death Process ◽  
Gene Repertoire ◽  
Teleost Fishes ◽  
Syngnathus Typhle ◽  
Or Gene ◽  
Or Genes

AbstractTeleost fishes perceive their environment through a range of sensory modalities, among which olfaction often plays an important role. Richness of the olfactory repertoire depends on the diversity of receptors coded by homologous genes classified into four families: OR, TAAR, VR1 and VR2. Herein, we focus on the OR gene repertoire. While independent large contractions of the OR gene repertoire associated with ecological transitions have been found in mammals, little is known about the diversity of the OR gene repertoire and its evolution within teleost fishes, a group that includes more than 34,000 living species. We analyzed genomes of 163 species representing diversity in this large group. We found a large range of variation in the number of functional OR genes, from 15 in Syngnathus typhle and Mola mola, to 429 in Mastacembelus armatus. The number of OR genes was higher in species with an extensively folded olfactory epithelium, that is, for example, when a multi-lamellar rosette was present in the olfactory organ. Moreover, the number of lamellae was correlated with the richness of the OR gene repertoire. While a slow and balanced birth-and-death process generally drives evolution of the OR gene repertoire, we inferred several episodes of high rates of gene loss, sometimes followed by large gains in the number of OR genes. These gains coincide with morphological changes of the olfactory organ and suggest a strong functional association between changes in the morphology and the evolution of the OR gene repertoire.

Green fluorescent protein (GFP) expression patterns in the olfactory epithelium of GFP transgenic cloned Jinhua pigs

2013 ◽  
Vol 95 (3) ◽  
pp. 319-329
Author(s):  
Atsushi Hirao ◽  
Tatsuo Kawarasaki ◽  
Kenjiro Konno ◽  
Satoko Enya ◽  
Masatoshi Shibata ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Olfactory Epithelium ◽  
Fluorescent Protein ◽  
Expression Patterns ◽  
Gfp Expression ◽  
Green Fluorescent

Selectivity and Response Characteristics of Human Olfactory Neurons

1997 ◽  
Vol 77 (3) ◽  
pp. 1606-1613 ◽  
Author(s):  
N. E. Rawson ◽  
G. Gomez ◽  
B. Cowart ◽  
J. G. Brand ◽  
L. D. Lowry ◽  
...  
Keyword(s):  
Calcium Concentration ◽  
Calcium Influx ◽  
Olfactory Neuron ◽  
Olfactory Neurons ◽  
Response Characteristics ◽  
Inositol 1,4,5 Trisphosphate ◽  
Transduction Mechanisms ◽  
Individual Odors ◽  
Second Messenger Pathways ◽  
Induced Changes

Rawson, N. E., G. Gomez, B. Cowart, J. G. Brand, L. D. Lowry, E. A. Pribitkin, and D. Restrepo. Selectivity and response characteristics of human olfactory neurons. J. Neurophysiol. 77: 1606–1613, 1997. Transduction mechanisms were investigated in human olfactory neurons by determining characteristics of odorant-induced changes in intracellular calcium concentration ([Ca2+]i). Olfactory neurons were freshly isolated from nasal biopsies, allowed to attach to coverslips, and loaded with the calcium-sensitive indicator fura-2. Changes in [Ca2+]i were studied in response to exposure to individual odors, or odorant mixtures composed to distinguish between transduction pathways mediated by adenosine 3′5′-monophosphate (cAMP; mix A) or inositol 1,4,5-trisphosphate (InsP3; mix B). Overall, 52% of biopsies produced one or more odorant-responsive olfactory neurons, whereas 24% of all olfactory neurons tested responded to odorant exposure with a change in [Ca2+]i. As in olfactory neurons from other species, the data suggest that odorant exposure elicited calcium influx via second-messenger pathways involving cAMP or InsP3. Unlike olfactory neurons from other species that have been tested, some human olfactory neurons responded to odorants with decreases in [Ca2+]i. Also in contrast with olfactory neurons from other species, human olfactory neurons were better able to discriminate between odorant mixtures in that no neuron responded to more than one type of odor or mixture. These results suggest the presence of a previously unreported type of olfactory transduction mechanism, and raise the possibility that coding of odor qualities in humans may be accomplished to some degree differently than in other vertebrates, with the olfactory neuron itself making a greater contribution to the discrimination process.

scholarly journals Variation in olfactory neuron repertoires is genetically controlled and environmentally modulated

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Ximena Ibarra-Soria ◽  
Thiago S Nakahara ◽  
Jingtao Lilue ◽  
Yue Jiang ◽  
Casey Trimmer ◽  
...  
Keyword(s):  
Olfactory Receptor ◽  
Sensory System ◽  
Dependent Manner ◽  
Olfactory Neuron ◽  
Neuronal Diversity ◽  
Cis Acting ◽  
Genetic And Environmental Factors ◽  
Or Gene ◽  
Different Strains ◽  
Subtype Distribution

The mouse olfactory sensory neuron (OSN) repertoire is composed of 10 million cells and each expresses one olfactory receptor (OR) gene from a pool of over 1000. Thus, the nose is sub-stratified into more than a thousand OSN subtypes. Here, we employ and validate an RNA-sequencing-based method to quantify the abundance of all OSN subtypes in parallel, and investigate the genetic and environmental factors that contribute to neuronal diversity. We find that the OSN subtype distribution is stereotyped in genetically identical mice, but varies extensively between different strains. Further, we identify cis-acting genetic variation as the greatest component influencing OSN composition and demonstrate independence from OR function. However, we show that olfactory stimulation with particular odorants results in modulation of dozens of OSN subtypes in a subtle but reproducible, specific and time-dependent manner. Together, these mechanisms generate a highly individualized olfactory sensory system by promoting neuronal diversity.

scholarly journals InsectOR – webserver for sensitive identification of insect olfactory receptor genes from non-model genomes

2020 ◽  
Author(s):  
Snehal D. Karpe ◽  
Vikas Tiwari ◽  
Sowdhamini Ramanathan
Keyword(s):  
Genome Annotation ◽  
Gene Prediction ◽  
Web Server ◽  
Olfactory Receptors ◽  
Rapid Prediction ◽  
Protein Receptors ◽  
Olfactory Receptor Genes ◽  
Or Gene ◽  
Or Genes ◽  
The Web

AbstractInsect Olfactory Receptors (ORs) are diverse family of membrane protein receptors responsible for most of the insect olfactory perception and communication, and hence they are of utmost importance for developing repellents or pesticides. Hence, accurate gene prediction of insect ORs from newly sequenced genomes is an important but challenging task. We have developed a dedicated web-server, ‘insectOR’, to predict and validate insect OR genes using multiple gene prediction algorithms, accompanied by relevant validations. It is possible to employ this sever nearly automatically and perform rapid prediction of the OR gene loci from thousands of OR-protein-to-genome alignments, resolve gene boundaries for tandem OR genes and refine them further to provide more complete OR gene models. InsectOR outperformed the popular genome annotation pipelines (MAKER and NCBI eukaryotic genome annotation) in terms of overall sensitivity at base, exon and locus level, when tested on two distantly related insect genomes. It displayed more than 95% nucleotide level precision in both tests. Finally, given the same input data and parameters, InsectOR missed less than 2% gene loci, in contrast to 55% loci missed by MAKER for Drosophila melanogaster. The web-server is freely available on the web at http://caps.ncbs.res.in/insectOR/. All major browsers are supported. Website is implemented in Python with Jinja2 for templating and bootstrap framework which uses HTML, CSS and JavaScript/Ajax. The core pipeline is written in Perl.

scholarly journals Hendra and Nipah Virus Infection in Cultured Human Olfactory Epithelial Cells

mSphere ◽  
2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Viktoriya Borisevich ◽  
Mehmet Hakan Ozdener ◽  
Bilal Malik ◽  
Barry Rockx
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Olfactory Epithelium ◽  
Neurological Disease ◽  
Nipah Virus ◽  
Hendra Virus ◽  
Olfactory Neurons ◽  
Zoonotic Pathogens ◽  
The Central Nervous System ◽  
A Site

ABSTRACT Henipaviruses are emerging zoonotic pathogens that can cause acute and severe respiratory and neurological disease in humans. The pathways by which henipaviruses enter the central nervous system (CNS) in humans are still unknown. The observation that human olfactory neurons are highly susceptible to infection with henipaviruses demonstrates that the olfactory epithelium can serve as a site of Henipavirus entry into the CNS. Henipaviruses are emerging zoonotic viruses and causative agents of encephalitis in humans. However, the mechanisms of entry into the central nervous system (CNS) in humans are not known. Here, we evaluated the possible role of olfactory epithelium in virus entry into the CNS. We characterized Hendra virus (HeV) and Nipah virus (NiV) infection of primary human olfactory epithelial cultures. We show that henipaviruses can infect mature olfactory sensory neurons. Henipaviruses replicated efficiently, resulting in cytopathic effect and limited induction of host responses. These results show that human olfactory epithelium is susceptible to infection with henipaviruses, suggesting that this could be a pathway for neuroinvasion in humans. IMPORTANCE Henipaviruses are emerging zoonotic pathogens that can cause acute and severe respiratory and neurological disease in humans. The pathways by which henipaviruses enter the central nervous system (CNS) in humans are still unknown. The observation that human olfactory neurons are highly susceptible to infection with henipaviruses demonstrates that the olfactory epithelium can serve as a site of Henipavirus entry into the CNS.

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