Blocking effect of Timberol® is exclusively mediated by hTAAR5.

<p>Each response was normalized to corresponding agonist alone. Left: Concentration-response curves (n = 3) of (A) azelaic acid and MOR42-3 and (B) nonanoic acid and hOR51E1. Right: Blocking effects (n = 3) of Timberol® (30 μM) on (A) MOR42-3-mediated responses to azelaic acid and (B) hOR51E-mediated responses to nonanoic acid. No significant blocking effects were observed. Gray bars represent the blocking effect of Timberol® (30 μM) on hTAAR5-mediated responses to TMA in a concentration close to calculated EC₅₀.</p

Pattern of expression of OR pseudogenes in different tissues.

<p>All OR pseudogenes with summed FPKM values >0.5 across all 16 from Body Map 2.0 are listed. The color intensity represents the FPKM value. Of the expressed pseudogenes, 58% belong to the 7E subfamily; genes in this family are indicated by bold letters.</p

Expression Profile of Ectopic Olfactory Receptors Determined by Deep Sequencing

<div><p>Olfactory receptors (ORs) provide the molecular basis for the detection of volatile odorant molecules by olfactory sensory neurons. The OR supergene family encodes G-protein coupled proteins that belong to the seven-transmembrane-domain receptor family. It was initially postulated that ORs are exclusively expressed in the olfactory epithelium. However, recent studies have demonstrated ectopic expression of some ORs in a variety of other tissues. In the present study, we conducted a comprehensive expression analysis of ORs using an extended panel of human tissues. This analysis made use of recent dramatic technical developments of the so-called Next Generation Sequencing (NGS) technique, which encouraged us to use open access data for the first comprehensive RNA-Seq expression analysis of ectopically expressed ORs in multiple human tissues. We analyzed mRNA-Seq data obtained by Illumina sequencing of 16 human tissues available from Illumina Body Map project 2.0 and from an additional study of OR expression in testis. At least some ORs were expressed in all the tissues analyzed. In several tissues, we could detect broadly expressed ORs such as OR2W3 and OR51E1. We also identified ORs that showed exclusive expression in one investigated tissue, such as OR4N4 in testis. For some ORs, the coding exon was found to be part of a transcript of upstream genes. In total, 111 of 400 OR genes were expressed with an FPKM (fragments per kilobase of exon per million fragments mapped) higher than 0.1 in at least one tissue. For several ORs, mRNA expression was verified by RT-PCR. Our results support the idea that ORs are broadly expressed in a variety of tissues and provide the basis for further functional studies.</p> </div

Evidence for a shape-based recognition of odorants <i>in vivo</i> in the human nose from an analysis of the molecular mechanism of lily-of-the-valley odorants detection in the Lilial and Bourgeonal family using the C/Si/Ge/Sn switch strategy

<div><p>We performed an analysis of possible mechanisms of ligand recognition in the human nose. The analysis is based on <i>in vivo</i> odor threshold determination and <i>in vitro</i> Ca²⁺ imaging assays with a C/Si/Ge/Sn switch strategy applied to the compounds Lilial and Bourgeonal, to differentiate between different molecular mechanisms of odorant detection. Our results suggest that odorant detection under threshold conditions is mainly based on the molecular shape, i.e. the van der Waals surface, and electrostatics of the odorants. Furthermore, we show that a single olfactory receptor type is responsible for odor detection of Bourgeonal at the threshold level in humans <i>in vivo</i>. Carrying out a QM analysis of vibrational energies contained in the odorants, there is no evidence for a vibration-based recognition.</p></div

Expression of other chemosensors in human tissues.

<p>TAARs show very weak or no expression in the investigated tissues, while the taste receptors TAS1R and TAS2R show detectable expression across the investigated tissues. The vomeronasal receptors (VN1R), namely VN1R1, show a widespread expression pattern.</p

Expression of signaling pathway components across tissues.

<p>Expression analysis of signaling components including, Gα_olf (GNAL), adenylyl cyclase III (ADCY3), CNG channel subunits (CNGA2, CNGA4 and CNGB1), calcium-activated chloride channel (ANO2) and the nucleotide exchange factor Ric8b (RIC8B). We also investigated the expression of accessory proteins including receptor-transporting proteins (RTP1 and RTP2) and receptor-enhancing proteins 1 (REEP1), as well as the expression of the olfactory marker protein (OMP), a specific marker for olfactory sensory neurons.</p

Analysis of OR transcripts across tissues. A:

<p>Analysis of the 20 most highly expressed ORs (summed FPKM >1). The graphic illustrates the presence of detected chimeric transcripts or unannotated untranslated regions in the upstream areas of the respective OR ORF. <b>B:</b> Overview of detected internal splicing events within the ORF of the 20 most highly expressed ORs. The heat map indicates the level of expression of the respective receptor and the detected internal splicing events (red frames). <b>C:</b> Schematic representation of detected internal splicing events of the broadly expressed OR51E1 and the testis-specific OR4N4.</p

Determination of Δ<i>F</i>_<i>bind</i>(<i>r</i>) and Δ<i>F</i>_<i>vib</i>(<i>r</i>).

<p>Δ<i>F</i>_<i>bind</i>(<i>r</i>) was calculated by linear regression of <i>ΔG</i>_<i>bind</i> from docking runs (A) or QM calculations (B) in reference to the average X–C distance <i>r</i> (X = C, Si, Ge, Sn). In a similar way, Δ<i>F</i>_<i>vib</i>(<i>r</i>) (C) was calculated by linear regression of <i>ΔE</i>_<i>vib</i> from QM calculations in reference to <i>r</i>. For (B) and (C), data points are shown as the energy difference to compound <b>2a</b>. (D) and (E) display Δ<i>F</i>_<i>bind</i>(<i>r</i>) and Δ<i>F</i>_<i>vib</i>(<i>r</i>) after and additional ab initio QM minimization of the ligands within the rigid protein binding site.</p

Assessment of exponential connection of odor threshold concentration [<i>O</i>] and X–C distance <i>r</i> according to Eq (2)¹.

<p>Assessment of exponential connection of odor threshold concentration [<i>O</i>] and X–C distance <i>r</i> according to Eq (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0182147#pone.0182147.e002" target="_blank">2</a>)<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0182147#t002fn001" target="_blank">¹</a>.</p

Detection of weakly and highly expressed ORs with RNA-Seq. A:

<p>Sample representation of read coverage of weakly and highly expressed ORs detected in the prostate and visualized by the Integrative Genomic Viewer. The gray segments indicate reads that were mapped onto the reference genome. The gene is indicated by black bars (exon) and thin lines (intron). Above, the read coverage is shown (detected and mapped counts/bases at each respective position). <b>B:</b> Each bar represents the number of OR genes (black) or OR pseudogenes (gray) that were expressed in one of the 16 investigated tissues with an FPKM value >0.1. The largest number of ORs were detected in testis, brain and ovary; only a few ORs were detected in skeletal muscle and liver. <b>C:</b> The bar diagram shows the number of ORs exclusively expressed in each tissue. Exclusively expressed ORs have greater FPKM values than 0.1 in the tissue indicated and are expressed at FPKM values lower than 0.1 in all other tissues. Testis had the greatest number of exclusively expressed ORs. In skeletal muscle, no exclusively expressed ORs were detected.</p