Springer protocols feed by Genetics/Genomics This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Pharmacology of Mammalian Olfactory Receptors
Mammalian species have evolved a large and diverse number of odorant receptors (ORs). These proteins comprise the largest family of G-protein-coupled receptors (GPCRs) known, amounting to ∼1,000 different receptors in the rodent. From the perspective of olfactory coding, the availability of such a vast number of chemosensory receptors poses several fascinating questions; in addition, such a large repertoire provides an attractive biological model to study ligand–receptor interactions. The limited functional expression of these receptors in heterologous systems, however, has greatly hampered attempts to deorp...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Functional Assay of Mammalian and Insect Olfactory Receptors Using Xenopus Oocytes
The large number of olfactory receptors (ORs) expressed by various mammalian and insect species, as well as the large number of potential odorant ligands, has made the pairing of odorants with receptors (de-orphaning) exceedingly difficult. These efforts are further complicated by difficulties in expressing ORs in many standard expression systems. Xenopus laevis oocytes offer a versatile expression platform for the de-orphaning and functional characterization of ORs. Two-electrode voltage clamp electrophysiology is a common and relatively straightforward approach to the functional assay of receptors expressed in Xenop...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Functional Characterization of Insect Olfactory Receptor Neurons Through In Vivo Approaches
We describe in this chapter the methods routinely used in our laboratory to stimulate, record, and analyze the activity of olfactory receptor neurons in moths or flies. (Source: Springer protocols feed by Genetics/Genomics)
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Single Cell RT-PCR Identification of Odorant Receptors Expressed by Olfactory Neurons
Mammals have between 400 and 1,300 functional odorant receptor (OR) genes in their genomes. Each olfactory sensory neuron in the nose expresses only one single type of OR out of this vast repertoire. The OR expressed by an olfactory sensory neuron determines its functional activity and wiring to the olfactory bulb. Therefore, the identification of the OR type expressed by individual neurons contributes to the understanding of the mechanisms of odorant perception. Here we describe the protocol that combines single cell RT-PCR and degenerate PCR to identify the OR expressed by single olfactory neurons. In a primary PCR react...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Human Olfactory Receptors: Recombinant Expression in the Baculovirus/Sf9 Insect Cell System, Functional Characterization, and Odorant Identification
Cell surface expression of recombinant olfactory receptors (ORs) is a major limitation in characterizing their functional nature. We have shown that the recombinant expression of a human OR, OR 17-210, in the baculovirus/Sf9 insect cell system allows this protein to be expressed at the cell surface. We used Ca2+ imaging to demonstrate that recombinant OR 17-210 produces cellular activities upon odorant stimulation with ketones. Furthermore, this expression and functional system has been used to show that the preincubation of Human Odorant Binding Protein 2A decrease the calcium response of OR 17-210 following stimulation b...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

A Robust, Rapid, and Simple Method of Producing Olfactory Receptors Using Commercial E. coli Cell-Free Systems
The first bottleneck in olfactory receptor (OR) studies is producing sufficient quantities of soluble, functional, and stable receptors. Commercial cell-free in vitro translation systems can be used to produce milligrams of soluble and functional receptors within several hours directly from plasmid DNA. The receptors can be purified using immunoaffinity chromatography and gel filtration, and can be analyzed using gel electrophoresis and with other standard techniques. (Source: Springer protocols feed by Genetics/Genomics)
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Olfactory Receptors in Human Airway Epithelia
Olfactory receptors (OR) represent one of the largest gene families in the human genome. In spite of a significant progress in deciphering the physiological functions of olfactory receptors, how the majority of these G-protein-coupled receptors are activated is still mostly a mystery. Consequently, for the majority of OR genes there are currently no assigned physiological or behavioral functions. Deciphering ligand specificities and physiological significance of human ORs is important for understanding how the human olfactory genome encodes odors, and how such odors drive human behavior in health and disease. Although OR g...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Deciphering Activation of Olfactory Receptors Using Heterologous Expression in Saccharomyces cerevisiae and Bioluminescence Resonance Energy Transfer
Hetero- and homo-oligomerization of G protein-coupled receptors (GPCRs) has been addressed in the past years using various approaches such as co-immunoprecipitation, fluorescence resonance energy transfer and bioluminescence resonance energy transfer (BRET). Here, we report the methodological details from a previously published study to investigate the relationships between oligomerization and activation states of olfactory receptors (ORs). This methodology combines heterologous expression of ORs in Saccharomyces cerevisiae and BRET assays on membrane fractions, in particular, upon odorant stimulation. We have demonstrated...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Next-Generation Sequencing of the Human Olfactory Receptors
Humans have approximately 400 intact olfactory receptors (ORs). Among this set there are a large number of variations between individuals, a subset of which affects receptor function and can lead to interindividual variation in olfactory perception. Technological progress and cost erosion in next-generation sequencing have given us the opportunity to determine the sequence of the entire OR gene set with high fidelity and to measure the extent of variation in this functional module across many individuals. Given that whole genome sequencing remains prohibitively expensive for this purpose, especially since the OR sub-genome...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

A Hit Map-Based Statistical Method to Predict Best Ligands for Orphan Olfactory Receptors: Natural Key Odorants Versus “Lock Picks”
Smell is a multidimensional chemical sense. It creates a perception of our odorous environment by integrating the information of a plethora of volatile chemicals with other sensory inputs, emotions and memories. We are almost always exposed to odorant mixtures, not just single chemicals. Olfactory processing of complex odorant mixtures, such as coffee or wine, first is decoded at the site of perception by the hundreds of different olfactory receptor types, each residing in the cilia of their olfactory sensory neurons in the nose. Often, only a few odorants from many are essential to determine complex olfactory perception. ...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

The Electrical Properties of Olfactory Receptors in the Development of Biological Smell Sensors
We present here the results of the investigation of the electrical properties of two olfactory receptors (ORs): rat, OR I7, and human, OR 17-40, which are of interest in the creation of smell nanobiosensors. Described here is our investigation comparing the results from experiments using electrochemical impedance spectroscopy with the theoretical predictions obtained from a recently developed impedance network protein analog. The changes in the OR response following excitation correlated with the protein conformational change. The satisfactory agreement between theory and experiment points to a promising development of a n...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Molecular Modelling of Odorant/Olfactory Receptor Complexes
Providing a rationale that associates a chemical structure of an odorant to its induced perception has been sought for a long time. To achieve this, a detailed atomic structure of both the odorant and the olfactory receptor must be known. State-of-the-art techniques to model the 3D structure of an olfactory receptor in complex with various odorants are presented here. These range from sequence alignment with known structures to molecular dynamics simulations in a realistic environment. (Source: Springer protocols feed by Genetics/Genomics)
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Identification of Olfactory Receptor Genes from Mammalian Genome Sequences
Olfaction is essential for the survival of mammals. Diverse odorant molecules in the environment are detected by olfactory receptors (ORs) expressed in the olfactory epithelium of the nasal cavity. In general, mammalian genomes harbor ∼1,000 OR genes, which form the largest multigene family in mammals. The recent advances in genome sequencing technology have enabled us to computationally identify nearly complete repertoires of OR genes from various organisms. Such studies have revealed that the numbers of OR genes are highly variable among organisms depending on their living environments. (Source: Springer protocols fe...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

HORDE: Comprehensive Resource for Olfactory Receptor Genomics
Olfactory receptors (ORs) constitute the largest gene family in the mammalian genome. The existence of these proteins underlies the nature of, and variability in, odorant perception. The Human Olfactory Receptor Data Explorer (HORDE, http://genome.weizmann.ac.il/horde/ ) is a free online resource, which presents a complete compendium of all OR genes and pseudogenes in the genome of human and four other vertebrates. HORDE includes three parts: (1) an automated pipeline, which mines OR gene and pseudogene sequences out of complete genomes, and generates gene symbols based...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news

Databases in SenseLab for the Genomics, Proteomics, and Function of Olfactory Receptors
We present here, the salient aspects of three databases: Olfactory Receptor Database (ORDB) is a repository of genomics and proteomics information of ORs; OdorDB stores information related to odorous compounds, specifically identifying those that have been shown to interact with olfactory rectors; and OdorModelDB disseminates information related to computational models of olfactory receptors (ORs). The data stored among these databases is integrated. Presented in this chapter are descriptions of these resources, which are part of the SenseLab suite of databases, a discussion of the computational infrastructure that enhance...
Source: Springer protocols feed by Genetics/Genomics - April 19, 2013 Category: Genetics & Stem Cells Source Type: news