Two classes of olfactory receptors in xenopus laevis

Freitag, Joachim; Krieger, Jürgen; Strotmann, Jörg; Breer, Heinz

doi:10.1016/0896-6273(95)90016-0

Cited by 237 publications

(207 citation statements)

References 23 publications

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“…Recent evolutionary studies showed that the phylogenetic diversity of class I ORs exceeds that of class II ORs and that class II ORs form a monophyletic group within class I ORs (Alioto and Ngai 2005;Niimura and Nei 2005). These findings suggest that class II ORs may have originated from class I ORs, consistent with their proposed functional distinction (Freitag et al 1995;Mezler et al 2001). Thus, the two nasal chemosensory systems appear to show a consistent pattern of a shift from receptors for water-soluble molecules to those for volatiles in the vertebrate transition from water to land, reflecting a rare case of adaptation to terrestrial life at the gene family level.…”

Section: Discussionsupporting

confidence: 76%

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Comparative genomic analysis identifies an evolutionary shift of vomeronasal receptor gene repertoires in the vertebrate transition from water to land

Shi¹,

Zhang²

2007

Genome Res.

202

235

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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.[Supplemental material is available online at www.genome.org.]Olfaction, or nasal chemoreception, plays a critical role in the daily life of vertebrates. The nasal cavity of most air-breathing vertebrates contains two distinct olfactory tissues/organs: the main olfactory epithelium (MOE) and the vomeronasal organ (VNO) (Dulac and Torello 2003). MOE-mediated olfaction and VNO-mediated olfaction use completely different receptors and signal transduction pathways, and excite different regions of the brain (Dulac and Torello 2003). It was initially thought that MOE and VNO have distinct functions, as MOE detects "ordinary" odorants whereas VNO is specialized for detecting pheromones (Dulac 1997;Buck 2000). This view is changing, as several studies suggested that the MOE can also detect pheromones, whereas the VNO can also detect ordinary odorants (Sam et al. 2001;Boehm et al. 2005;Mandiyan et al. 2005;Yoon et al. 2005;Baxi et al. 2006). Here, pheromones refer to a loosely defined class of chemicals that are emitted and sensed by individuals of the same species to elicit sexual/social behaviors and physiological changes. Examples of pheromone-related behaviors and physiological changes include individual recognition, induction of early puberty, block of pregnancy, and male-male aggression (Keverne 1999).The molecular biology of vertebrate olfaction is best understood in the laboratory mouse Mus m...

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Section: Discussionsupporting

confidence: 76%

“…In fact, two classes of odorant receptors (ORs) are known in vertebrates (Freitag et al 1995). Heterologous cells expressing frog class II ORs and class I ORs have been shown to respond to volatile and water-solvable molecules, respectively (Mezler et al 2001).…”

Section: Evolution Of the Vertebrate V2r Gene Repertoirementioning

confidence: 99%

Comparative genomic analysis identifies an evolutionary shift of vomeronasal receptor gene repertoires in the vertebrate transition from water to land

Shi¹,

Zhang²

2007

Genome Res.

202

235

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“…Previous work by the Breer group [18] has suggested that the adult middle cavity contains OR class I-expressing neurons (subgroup alpha in Niimura and Nei nomenclature, [19,20]). For one of these OR class I receptors amino acid responses have been shown [21], so this class of receptors would be a plausible candidate for mediating amino acid responses in ciliated neurons.…”

Section: Discussionmentioning

confidence: 99%

Coordinated shift of olfactory amino acid responses and V2R expression to an amphibian water nose during metamorphosis

Syed

Sansone

Hassenklöver

et al. 2016

Cell. Mol. Life Sci.

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All olfactory receptors identified in teleost fish are expressed in a single sensory surface, whereas mammalian olfactory receptor gene families segregate into different olfactory organs, chief among them the main olfactory epithelium expressing ORs and TAARs, and the vomeronasal organ expressing V1Rs and V2Rs. A transitional stage is embodied by amphibians, with their vomeronasal organ expressing more 'modern', later diverging V2Rs, whereas more 'ancient', earlier diverging V2Rs are expressed in the main olfactory epithelium.During metamorphosis the main olfactory epithelium of Xenopus tadpoles transforms into an air-filled cavity (principal cavity, air nose), whereas a newly formed cavity (middle cavity) takes over the function of a water nose. We report here that larval expression of ancient V2Rs is gradually lost from the main olfactory epithelium as it transforms into the air nose.Concomitantly, ancient v2r gene expression begins to appear in the basal layers of the newly forming water nose. We observe the same transition for responses to amino acid odorants, consistent with the hypothesis that amino acid responses may be carried by V2R receptors.3

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“…Freitag et al [14] reported that the middle chamber epithelium in the MC expresses fish-like olfactory receptors, whereas the olfactory epithelium in the PC expresses mammalian-like olfactory receptors. Rössler et al [29] demonstrated that the olfactory marker protein, which is exclusively expressed in vertebrate mature olfactory receptor neurons, shows differential expression between the olfactory epithelium and the middle patterns of axonal projection from each of the three nasal chambers to the olfactory bulb by anterograde labeling using Di-I.…”

Section: Discussionmentioning

confidence: 99%

Expression Patterns of Glycoconjugates in the Three Distinctive Olfactory Pathways of the Clawed Frog, Xenopus laevis.

Saito

Taniguchi

2000

The Journal of Veterinary Medical Science

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Two classes of olfactory receptors in xenopus laevis

Cited by 237 publications

References 23 publications

Comparative genomic analysis identifies an evolutionary shift of vomeronasal receptor gene repertoires in the vertebrate transition from water to land

Comparative genomic analysis identifies an evolutionary shift of vomeronasal receptor gene repertoires in the vertebrate transition from water to land

Coordinated shift of olfactory amino acid responses and V2R expression to an amphibian water nose during metamorphosis

Expression Patterns of Glycoconjugates in the Three Distinctive Olfactory Pathways of the Clawed Frog, Xenopus laevis.

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