scholarly journals Transcriptomic profiling of sex-specific olfactory neurons reveals subset-specific receptor expression in C. elegans

2021 ◽  
Author(s):  
Douglas K Reilly ◽  
Erich M Schwarz ◽  
Caroline S Muirhead ◽  
Annalise N Robidoux ◽  
Igor Antoscheckin ◽  
...  
Keyword(s):  
Neural Coding ◽  
Radial Symmetry ◽  
Receptor Expression ◽  
Double Knockout ◽  
Olfactory Neurons ◽  
Transcriptomic Profiling ◽  
C Elegans ◽  
Expression Of Genes ◽  
Gfp Reporter ◽  
Male Specific

The nematode Caenorhabditis elegans utilizes chemosensation to navigate an ever-changing environment for its survival. A class of secreted small-molecule pheromones, termed ascarosides, play an important role in olfactory perception by affecting a host of biological function ranging from development to behavior. The ascaroside ascr#8 mediates sex-specific behaviors, driving avoidance in hermaphrodites and attraction in males. Males sense ascr#8 via the ciliated male-specific cephalic sensory (CEM) neurons, which exhibit radial symmetry along dorsal-ventral and left-right axes. Calcium imaging studies suggest a complex neural coding mechanism that translates stochastic physiological responses in these neurons to reliable behavioral outputs. To test the hypothesis that the neurophysiological complexity arises from differential expression of genes within subsets of these neurons, we performed cell-specific transcriptomic profiling of these sensory neurons. Expression profiling revealed between 20 and 639 genes enriched at least two-fold per CEM neuron and identified multiple G protein coupled receptor (GPCR) candidates enriched in non-overlapping subsets of CEM neurons. GFP reporter analysis confirmed that RNA expression of two of the GPCR genes, srw-97 and dmsr-12, is enriched in specific subsets of the CEM neurons. Single CRISPR-Cas9 knockouts of either srw-97 or dmsr-12 resulted in partial defects, while a double knockout of both srw-97 and dmsr-12 completely abolished the attractive response to ascr#8, suggesting that each receptor acts in a non-redundant manner in discrete olfactory neurons. Together, our results suggest that the evolutionarily distinct GPCRs SRW-97 and DMSR-12 act to facilitate male-specific sensation of ascr#8 through discrete subsets of CEM neurons.

scholarly journals Distinct neuropeptide-receptor modules regulate a sex-specific behavioral response to a pheromone

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Douglas K. Reilly ◽  
Emily J. McGlame ◽  
Elke Vandewyer ◽  
Annalise N. Robidoux ◽  
Caroline S. Muirhead ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Behavioral Response ◽  
Receptor Expression ◽  
Specific Response ◽  
Sensory Cues ◽  
Animal Kingdom ◽  
Dioecious Species ◽  
C Elegans ◽  
Biochemical Studies ◽  
Male Specific

AbstractDioecious species are a hallmark of the animal kingdom, with opposing sexes responding differently to identical sensory cues. Here, we study the response of C. elegans to the small-molecule pheromone, ascr#8, which elicits opposing behavioral valences in each sex. We identify a novel neuropeptide-neuropeptide receptor (NP/NPR) module that is active in males, but not in hermaphrodites. Using a novel paradigm of neuropeptide rescue that we established, we leverage bacterial expression of individual peptides to rescue the sex-specific response to ascr#8. Concurrent biochemical studies confirmed individual FLP-3 peptides differentially activate two divergent receptors, NPR-10 and FRPR-16. Interestingly, the two of the peptides that rescued behavior in our feeding paradigm are related through a conserved threonine, suggesting that a specific NP/NPR combination sets a male state, driving the correct behavioral valence of the ascr#8 response. Receptor expression within pre-motor neurons reveals novel coordination of male-specific and core locomotory circuitries.

scholarly journals The C.elegans AWA Olfactory Neuron Fires Calcium-Mediated All-or-None Action Potentials

2018 ◽  
Author(s):  
Qiang Liu ◽  
Philip B. Kidd ◽  
May Dobosiewicz ◽  
Cornelia I. Bargmann
Keyword(s):  
Calcium Imaging ◽  
Action Potentials ◽  
Neural Coding ◽  
Patch Clamp Recording ◽  
Olfactory Neurons ◽  
C Elegans ◽  
Coding Schemes ◽  
Current Voltage ◽  
Ion Substitution ◽  
Specialized Function

SummaryWe find, unexpectedly, that C. elegans neurons can encode information through regenerative all-or-none action potentials. In a survey of current-voltage relationships in C. elegans neurons, we discovered that AWA olfactory neurons generate membrane potential spikes with defining characteristics of action potentials. Ion substitution experiments, pharmacology, and mutant analysis identified a voltage-gated CaV1 calcium channel and a Shaker-type potassium channel that underlie action potential dynamics in AWA. Simultaneous patch-clamp recording and calcium imaging in AWA revealed spike-associated calcium signals that were also observed after odor stimulation of intact animals, suggesting that natural odor stimuli induce AWA action potentials. The stimulus regimes that elicited action potentials match AWA’s proposed specialized function in climbing odor gradients. Our results provide evidence that C. elegans can use digital as well as analog coding schemes, expand the computational repertoire of its nervous system, and inform future modeling of its neural coding and network dynamics.

scholarly journals Distinct Neuropeptide-Receptor Modules Regulate a Sex-Specific Behavioral Response to a Pheromone

2020 ◽  
Author(s):  
Douglas K. Reilly ◽  
Emily J. McGlame ◽  
Elke Vandewyer ◽  
Annalise M. Robidoux ◽  
Haylea T. Northcott ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Behavioral Response ◽  
Receptor Expression ◽  
Specific Response ◽  
Sensory Cues ◽  
Animal Kingdom ◽  
Dioecious Species ◽  
C Elegans ◽  
Biochemical Studies ◽  
Male Specific

AbstractDioecious species are a hallmark of the animal kingdom, with opposing sexes responding differently to identical sensory cues. Here, we study the response of C. elegans’ to the small-molecule pheromone, ascr#8, which elicits opposing behavioral valences in each sex. We identify a novel neuropeptide-neuropeptide receptor (NP/NPR) module that is active in males, but not in hermaphrodites. Using a novel paradigm of neuropeptide rescue that we established, we leverage bacterial expression of individual peptides to rescue the sex-specific response to ascr#8. Concurrent biochemical studies confirmed individual FLP-3 peptides differentially activate two divergent receptors, NPR-10 and FRPR-16. Interestingly, the two of the peptides that rescued behavior in our feeding paradigm are related through a conserved threonine, suggesting that a specific NP/NPR combination sets a male state, driving the correct behavioral valence of the ascr#8 response. Receptor expression within pre-motor neurons reveals novel coordination of male-specific and core locomotory circuitries.

scholarly journals Timing mechanism of sexually dimorphic nervous system differentiation

2018 ◽  
Author(s):  
Laura Pereira ◽  
Florian Aeschimann ◽  
Chen Wang ◽  
Hannah Lawson ◽  
Esther Serrano-Saiz ◽  
...  
Keyword(s):  
Nervous System ◽  
Transcription Factors ◽  
Sexual Maturation ◽  
Sexual Differentiation ◽  
Rna Binding ◽  
Receptor Expression ◽  
Sexually Dimorphic ◽  
Neuron Type ◽  
C Elegans ◽  
Male Specific

ABSTRACTIn all animals, sexual differentiation of somatic tissue is precisely timed, yet the molecular mechanisms that control the timing of sexual differentiation, particularly in the brain, are poorly understood. We have used sexually dimorphic molecular, anatomical and behavioral features of the C. elegans nervous system to decipher a regulatory pathway that controls the precise timing of sexual differentiation. We find that the sexually dimorphic differentiation of postmitotic neurons in the male nervous system is abrogated in animals that carry a mutation in the miRNA let-7 and prematurely executed in animals either lacking the let-7 inhibitor lin-28, or the direct let-7 target lin-41, an RNA-binding, posttranscriptional regulator. We show that an isoform of a phylogenetically conserved transcription factor, lin-29a, is a critical target of LIN-41 in controlling sexual maturation of sex-shared neurons. lin-29a is expressed in a male-specific manner in a subset of sex-shared neurons at the onset of sexual maturation. lin-29a acts cell-autonomously in these neurons to control the expression of sexually dimorphic neurotransmitter switches, sensory receptor expression, neurite anatomy and connectivity, and locomotor behavior. lin-29a is not only required but also sufficient to impose male-specific features at earlier stages of development and in the opposite sex. The temporal, sexual and spatial specificity of lin-29a expression is controlled intersectionally through the lin-28/let-7/lin-41 heterochronic pathway, sex chromosome configuration and neuron type-specific terminal selector transcription factors. Two Doublesex-like transcription factors represent additional neuron-type specific targets of LIN-41 and are regulated in a similar intersectional manner, indicating the existence of modular outputs downstream of the heterochronic pathway. In conclusion, we have provided insights into the molecular logic of the timing of sexual differentiation in the C. elegans nervous system. Remarkably, the lin28/let7 axis also controls the timing of sexual differentiation in mice and humans thereby hinting toward a striking universality of the control mechanisms of sexual differentiation.

The Caenorhabditis elegans odr-2 Gene Encodes a Novel Ly-6-Related Protein Required for Olfaction

Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 211-224 ◽  
Author(s):  
Joseph H Chou ◽  
Cornelia I Bargmann ◽  
Piali Sengupta
Keyword(s):  
Caenorhabditis Elegans ◽  
Motor Neurons ◽  
Amino Terminus ◽  
Signaling Proteins ◽  
Related Protein ◽  
Olfactory Neurons ◽  
Unique Role ◽  
C Elegans ◽  
Founding Member ◽  
High Concentrations

Abstract Caenorhabditis elegans odr-2 mutants are defective in the ability to chemotax to odorants that are recognized by the two AWC olfactory neurons. Like many other olfactory mutants, they retain responses to high concentrations of AWC-sensed odors; we show here that these residual responses are caused by the ability of other olfactory neurons (the AWA neurons) to be recruited at high odor concentrations. odr-2 encodes a membrane-associated protein related to the Ly-6 superfamily of GPI-linked signaling proteins and is the founding member of a C. elegans gene family with at least seven other members. Alternative splicing of odr-2 yields three predicted proteins that differ only at the extreme amino terminus. The three isoforms have different promoters, and one isoform may have a unique role in olfaction. An epitope-tagged ODR-2 protein is expressed at high levels in sensory neurons, motor neurons, and interneurons and is enriched in axons. The AWC neurons are superficially normal in their development and structure in odr-2 mutants, but their function is impaired. Our results suggest that ODR-2 may regulate AWC signaling within the neuronal network required for chemotaxis.

scholarly journals Loss of Mafb and Maf distorts myeloid cell ratios and disrupts fetal mouse testis vascularization and organogenesis

2021 ◽  
Author(s):  
Shu-Yun Li ◽  
Xiaowei Gu ◽  
Anna Heinrich ◽  
Emily G. Hurley ◽  
Blanche Capel ◽  
...  
Keyword(s):  
Sertoli Cells ◽  
Immune Cell ◽  
Gonad Development ◽  
Myeloid Cell ◽  
Cell Types ◽  
Double Knockout ◽  
Fetal Mouse ◽  
Testis Differentiation ◽  
Male Specific ◽  
Testis Cord

AbstractTestis differentiation is initiated when Sry in pre-Sertoli cells directs the gonad toward a male-specific fate. Sertoli cells are essential for testis development, but cell types within the interstitial compartment, such as immune and endothelial cells, are also critical for organ formation. Our previous work implicated macrophages in fetal testis morphogenesis, but little is known about genes underlying immune cell development during organogenesis. Here we examine the role of the immune-associated genes Mafb and Maf in mouse fetal gonad development, and we demonstrate that deletion of these genes leads to aberrant hematopoiesis manifested by supernumerary gonadal monocytes. Mafb;Maf double knockout embryos underwent initial gonadal sex determination normally, but exhibited testicular hypervascularization, testis cord formation defects, Leydig cell deficit, and a reduced number of germ cells. In general, Mafb and Maf alone were dispensable for gonad development; however, when both genes were deleted, we observed significant defects in testicular morphogenesis, indicating that Mafb and Maf work redundantly during testis differentiation. These results demonstrate previously unappreciated roles for Mafb and Maf in immune and vascular development and highlight the importance of interstitial cells in gonadal differentiation.Summary statementDeletion of Mafb and Maf genes leads to supernumerary monocytes in fetal mouse gonads, resulting in vascular, morphogenetic, and differentiation defects during testicular organogenesis.

scholarly journals Loss of Atg2b and Gskip impairs the maintenance of the hematopoietic stem cell pool size

2021 ◽  
Author(s):  
Shun-suke Sakai ◽  
Atsushi Hasegawa ◽  
Ryosuke Ishimura ◽  
Naoki Tamura ◽  
Shun Kageyama ◽  
...  
Keyword(s):  
Myeloproliferative Neoplasm ◽  
Pool Size ◽  
Double Knockout ◽  
Hematopoietic Stem ◽  
Cell Pool ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Differentiation Efficiency ◽  
Stem Cell Pool

A germline copy number duplication of chromosome 14q32, which contains ATG2B and GSKIP , was identified in families with myeloproliferative neoplasm (MPN). Herein, we show that mice lacking both Atg2b and Gskip , but not either alone, exhibited decreased hematopoiesis, resulting in death in utero accompanied by anemia. In marked contrast to MPN patients with duplication of ATG2B and GSKIP , the number of hematopoietic stem cells (HSCs), in particular long-term HSCs, in double knockout fetal livers were significantly decreased due to increased cell death. Although the remaining HSCs still had the ability to differentiate into hematopoietic progenitor cells, the differentiation efficiency was quite low. Remarkably, mice with knockout of Atg2b or Gskip alone did not show any hematopoietic abnormality. Mechanistically, while loss of both genes had no effect on autophagy, it increased the expression of genes encoding enzymes involved in oxidative phosphorylation. Taken together, our results indicate that Atg2b and Gskip play a synergistic effect in maintaining the pool size of HSCs.

scholarly journals Small Molecule Stabilization of PINK-1/PINK1 Improves Neurodegenerative Disease

2021 ◽  
Author(s):  
Elissa Tjahjono ◽  
Jingqi Pei ◽  
Alexey V Revtovich ◽  
Terri-Jeanne E Liu ◽  
Alisha Swadi ◽  
...  
Keyword(s):  
Neurodegenerative Disease ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Mitochondrial Fragmentation ◽  
Atp Production ◽  
C Elegans ◽  
Mitochondrial Homeostasis ◽  
Phenotypic Screen ◽  
Gfp Reporter ◽  
Common Causes

Macroautophagic recycling of dysfunctional mitochondria, known as mitophagy, is essential for mitochondrial homeostasis and cell viability. Accumulation of defective mitochondria and impaired mitophagy have been widely implicated in many neurodegenerative diseases, and loss-of-function mutations of two regulators of mitophagy, PINK1 and Parkin, are amongst the most common causes of recessive Parkinson's disease. Activation of mitophagy via pharmacological treatments may be a feasible approach for combating neurodegeneration. In this effort, we screened ~45,000 small molecules for the ability to activate mitophagy. A high-throughput, whole-organism, phenotypic screen was conducted by monitoring stabilization of PINK-1/PINK1, a key event in mitophagy activation, in a Caenorhabditis elegans strain carrying a Ppink-1::PINK-1::GFP reporter. We obtained eight hits that induced mitophagy, as evidenced by increased mitochondrial fragmentation and autophagosome formation. Several of the compounds also reduced ATP production, oxygen consumption, mitochondrial mass, and/or mitochondrial membrane potential. Importantly, we found that treatment with two compounds, which we named PS83 and PS106 (more commonly known as sertraline) reduced neurodegenerative disease phenotypes (including delayed paralysis in a C. elegans Alzheimer's model) in a PINK-1/PINK1-dependent manner. This report presents a promising step toward the identification of compounds that will stimulate mitochondrial turnover.

mab-3, a gene required for sex-specific yolk protein expression and a male-specific lineage in C. elegans

Cell ◽  
1988 ◽  
Vol 54 (7) ◽  
pp. 1019-1031 ◽  
Author(s):  
Michael M. Shen ◽  
Jonathan Hodgkin
Keyword(s):  
Protein Expression ◽  
Yolk Protein ◽  
C Elegans ◽  
Male Specific

Creation of Low-Copy Integrated Transgenic Lines in Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1217-1226 ◽  
Author(s):  
Vida Praitis ◽  
Elizabeth Casey ◽  
David Collar ◽  
Judith Austin
Keyword(s):  
Caenorhabditis Elegans ◽  
Expression Level ◽  
Dna Arrays ◽  
Extrachromosomal Dna ◽  
C Elegans ◽  
Microparticle Bombardment ◽  
Alternative Method ◽  
Extrachromosomal Array ◽  
Gfp Reporter ◽  
Transgenic Lines

Abstract In Caenorhabditis elegans, transgenic lines are typically created by injecting DNA into the hermaphrodite germline to form multicopy extrachromosomal DNA arrays. This technique is a reliable means of expressing transgenes in C. elegans, but its use has limitations. Because extrachromosomal arrays are semistable, only a fraction of the animals in a transgenic extrachromosomal array line are transformed. In addition, because extrachromosomal arrays can contain hundreds of copies of the transforming DNA, transgenes may be overexpressed, misexpressed, or silenced. We have developed an alternative method for C. elegans transformation, using microparticle bombardment, that produces single- and low-copy chromosomal insertions. Using this method, we find that it is possible to create integrated transgenic lines that reproducibly express GFP reporter constructs without the variations in expression level and pattern frequently exhibited by extrachromosomal array lines. In addition, we find that low-copy integrated lines can also be used to express transgenes in the C. elegans germline, where conventional extrachromosomal arrays typically fail to express due to germline silencing.

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