Coding genes and molecular structures of the diffusible signalling proteins (pheromones) of the polar ciliate, Euplotes nobilii

Vallesi, Adriana; Alimenti, Claudio; Pedrini, Bill; Giuseppe, Graziano Di; Dini, Fernando; Wüthrich, Kurt; Luporini, Pierangelo

doi:10.1016/j.margen.2012.03.004

Cited by 11 publications

(15 citation statements)

References 34 publications

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“…As previously discussed [3,10,21], the two homologous protein families of E. nobilii psychrophilic pheromones and E. raikovi mesophilic pheromones differ significantly in the composition of polar, hydrophobic and aromatic amino acids, in global hydrophilicity and hydrophobicity, as well as in various aspects of their three-dimensional structures. It will now be interesting to explore the extent to which these physico-chemical and structural variations can be related to variations of the stability of the folded proteins.…”

Section: Discussionmentioning

confidence: 93%

“…These water-borne “pheromones” are functionally associated with the genetic mechanism of the mating types and act as prototypic autocrine (autologous) growth factors and as paracrine (heterologous) inducers of mating pair formation [6,7]. In addition to the full-length coding gene sequences [8,9,10], the three-dimensional molecular structures of a significant number of pheromones were determined by NMR spectroscopy in solution, firstly, from the temperate-water species, E. raikovi [11,12,13,14,15,16,17], and subsequently from the polar-water species, E. nobilii [18,19,20]. These mesophilic ( E. raikovi ) and psychrophilic ( E. nobilii ) pheromone families, both characterized by small, helical and disulfide-rich proteins of 37 to 63 amino acids, thus represent an interesting source of material for structure based comparative studies of protein adaptation to cold.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic Stability of Psychrophilic and Mesophilic Pheromones of the Protozoan Ciliate Euplotes

Geralt

Alimenti

Vallesi

et al. 2013

Biology

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Three psychrophilic protein pheromones (En-1, En-2 and En-6) from the polar ciliate, Euplotes nobilii, and six mesophilic pheromones (Er-1, Er-2, Er-10, Er-11, Er-22 and Er-23) from the temperate-water sister species, Euplotes raikovi,were studied in aqueous solution for their thermal unfolding and refolding based on the temperature dependence of their circular dichroism (CD) spectra. The three psychrophilic proteins showed thermal unfolding with mid points in the temperature range 55–70 °C. In contrast, no unfolding was observed for any of the six mesophilic proteins and their regular secondary structures were maintained up to 95 °C. Possible causes of these differences are discussed based on comparisons of the NMR structures of the nine proteins.

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Section: Discussionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Thermodynamic Stability of Psychrophilic and Mesophilic Pheromones of the Protozoan Ciliate Euplotes

Geralt

Alimenti

Vallesi

et al. 2013

Biology

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“…However, their structure and mechanisms of expression have only recently been determined, and only in Tetrahymena (Cervantes et al 2013) and Paramecium (Singh et al 2014), for which full genome mapping is available (Aury et al 2006;Eisen et al 2006). In Euplotes, knowledge remains limited to the expressed macronuclear versions of the mating type genes (Vallesi et al , 2010b(Vallesi et al , 2012, and nothing is yet known about the unexpressed micronuclear versions of these genes.…”

Section: Discussionmentioning

confidence: 99%

“…Seven E. nobilii pheromones (collectively designated as "En") are known for their primary amino acid sequences ( Figure 4A): three (En-1, En-2, and En-6) are specific to Antarctic strains and four (En-A1, En-A2, En-A3 and En-A4) are specific to Arctic ones (Vallesi et al , 2012. The NMR solution structures are known only for four of them, which could be purified in larger amounts, namely En-1, En-2, En-6 and En-A1 Placzek et al 2007;Di Giuseppe et al 2011) ( Figure 4B).…”

Section: Euplotes Nobilii Pheromonesmentioning

confidence: 99%

Ciliate pheromone structures and activity: a review

Luporini

Alimenti

Vallesi

2014

Italian Journal of Zoology

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As in animals and other multicellular organisms, protozoan ciliates communicate via diffusible signalling pheromones. These pheromones have been identified in the culture supernatant of various species. However, their isolation and definitive structural characterization have been achieved only in species of Blepharisma and Euplotes. With the exception of the two B. japonicum pheromones represented by a tryptophan-related molecule and a glycoprotein, all the other pheromones isolated from Euplotes species are proteins that vary in extension between 38 and 109 amino acids. They form species-specific families of structurally homologous members, in full accord with their multi-allelic determination at an apparently single genetic locus. The determination of the Nuclear Magnetic Resonance (NMR) solution structures of E. raikovi and E. nobilii pheromones has provided direct evidence that, although structurally unique, Euplotes pheromones adopt a common, speciesspecific three-helix folding. This close structural homology among members of the same family well accounts for the pheromone capacity to compete with one another in cell receptor binding reactions and elicit context-dependent, autocrine (growth-promoting) or paracrine (mating-inducing) cell responses.

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“…This collection was for a long time essentially used to investigate molecular mechanisms underlying cold adaptation (Pedrini et al, 2007;Alimenti et al, 2009;Vallesi et al, 2010Vallesi et al, , 2012Chiappori et al, 2012;Candelori et al, 2013;Geralt et al, 2013). Only more recently has it turned out to be of research interest also within a biogeographic and ecological perspective, in relation to morphological and genetic evidence that co-specificity exists among strains inhabiting opposite sides of the globe (Di Giuseppe et al, 2011, 2013a.…”

Section: Introductionmentioning

confidence: 99%

Genetic relationships in bipolar species of the protist ciliate, Euplotes

et al. 2015

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Protists thrive in polar oceans, where they\ud represent a major driving force for globally important\ud biogeochemical cycles and a key food-web component.\ud Their biogeography is frequently associated to\ud bipolar patterns of distribution. Although conceptually\ud well supported by apparently unrestricted migration\ud rates, the experimental certification of these patterns\ud copes with the protist paucity of morphological\ud characters with taxonomic value and difficulties in\ud applying conventional species concepts. We studied\ud three marine species of the ciliate Euplotes, E.\ud euryhalinus, E. nobilii, and E. petzi, for their bipolar\ud distribution by comparing the SSU-rRNA gene sequences\ud and mating interactions of Antarctic,\ud Patagonian, and Arctic strains. Each species was\ud analogously found not to carry significantly varied\ud SSU-rRNA gene sequences, implying a common\ud occurrence of trans-equatorial genetic mixing. However,\ud mating analyses revealed significant interspecies\ud differences. Scarce Antarctic 9 Arctic strain\ud mating compatibility distinguished E. petzi from E.\ud euryhalinus and E. nobilii, in which mating pairs\ud between Antarctic and Arctic strains were successfully\ud induced. Yet, E. nobilii was the only one of the two\ud species to show cross-fertilizing and fertile mating\ud pairs. Taking the biological concept of species as\ud discriminatory, it was thus concluded that only E.\ud nobilii warrants the definition of genuine bipolar\ud species

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Coding genes and molecular structures of the diffusible signalling proteins (pheromones) of the polar ciliate, Euplotes nobilii

Cited by 11 publications

References 34 publications

Thermodynamic Stability of Psychrophilic and Mesophilic Pheromones of the Protozoan Ciliate Euplotes

Thermodynamic Stability of Psychrophilic and Mesophilic Pheromones of the Protozoan Ciliate Euplotes

Ciliate pheromone structures and activity: a review

Genetic relationships in bipolar species of the protist ciliate, Euplotes

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