Peptide and protein pheromones in amphibians

Mate attraction in Aplysia involves a long-distance water-borne signal (attractin) that is released during egg laying. Other pheromones are predicted to be released during egg laying that act in concert with albumen gland attractin to stimulate attraction, but their identities are unknown. To identify other candidate water-borne pheromones, we employed differential library screening of an albumen gland cDNA library, Northern blot analysis, purification, characterization, cloning, and expression of albumen gland proteins, matrix-assisted laser desorption ionization mass spectrometry, pheromone secretion assays, behavioral bioassays, immunolocalization studies, and comparative genomics. Four genes, Alb-23, Alb-24, Alb-69, and Alb-172, were highly expressed in Aplysia californica albumen glands and encoded novel proteins. The products of the Alb-24 ("enticin") and Alb-172 ("temptin") precursors were soluble and highly abundant in albumen gland extracts, whereas Alb-23 and Alb-69 were membrane-associated proteins. A comparative analysis showed that the predicted Aplysia brasiliana enticin and temptin proteins were 90 and 91% identical, respectively, to their A. californica homologs. T-maze attraction bioassay studies have previously demonstrated that egg cordons alone are attractive to Aplysia but that attractin alone is not. In the present study, however, the combination of attractin, enticin, and temptin was found to be significantly attractive to potential mates and doubled the number of animals attracted to this stimulus compared with control animals. The combined data strongly suggest that enticin and temptin are novel candidate waterborne protein pheromones that act in concert with attractin to attract Aplysia to form and maintain egglaying and mating aggregations.Chemical communication is the most ancient form of communication and is used by most, if not all, animals examined, including ciliated protozoans (1), yeast (2), insects (3-5), mollusks (6 -10), worms (11, 12), fish (13), amphibians (14 -16), rodents (17, 18), and humans (19).Aplysia are simultaneous hermaphrodites that do not normally fertilize their own eggs. Field studies (20 -23) have shown that they are solitary animals that move into breeding aggregations during the reproductive season. The aggregations usually contain both mating and egg-laying animals and are associated with masses of recently deposited egg cordons, often deposited one on top of another. Most of the egg-laying animals mate simultaneously as females, even though mating does not trigger reflex ovulation (24), suggesting that egg laying precedes mating in the aggregation and that egg laying may release pheromones that establish and maintain the aggregation (25,27,28). The pheromonal factors seem to be derived from the egg cordon rather than the egg layer and some are waterborne (29).One of these water-borne pheromonal attractants (attractin) has been isolated from eluates of Aplysia californica egg cordons and characterized. Attractin is a 58-residue N-glycosylated protein with ...

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“…Ref. 53). If mate attraction were the sole function of attractin, one might expect that the pheromone would attract only conspecifics.…”

Section: Figmentioning

confidence: 99%

Characterization of Aplysia Enticin and Temptin, Two Novel Water-borne Protein Pheromones That Act in Concert with Attractin to Stimulate Mate Attraction

Cummins

Nichols

Amare

et al. 2004

Journal of Biological Chemistry

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“…Several proteinaceous pheromones of amphibians have been characterized and range in size from 10 to over 200 aa (reviewed in Kikuyama et al, 2002). Some of these pheromones are prone to rapid diversification via amino acid substitutions, which may promote speciation (Palmer et al, 2005(Palmer et al, , 2007a(Palmer et al, , 2007bWatts et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Evolutionary shifts in courtship pheromone composition revealed by EST analysis of plethodontid salamander mental glands

Kiemnec-Tyburczy

Watts

Gregg

et al. 2009

Gene

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“…In this study, therefore, we characterized attractins from four Aplysia species and have identified the residues that are important for attraction activity. We conclude that, in contrast to the species-specific, water-borne peptide pheromonal attractants in amphibians (17)(18)(19)(20), the attractins are an unusual family of protein pheromones in invertebrates that are not species specific. depilans, extracted, and purified by RP-HPLC, and attractin was characterized as described for A. californica attractin (2).…”

mentioning

confidence: 77%

Structural and functional analysis of Aplysia attractins, a family of water-borne protein pheromones with interspecific attractiveness

Painter

Cummins

Nichols

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Mate attraction in Aplysia involves a long-distance water-borne signal (the protein pheromone attractin), which is released during egg laying. Aplysia californica attractin attracts species that produce closely related attractins, such as Aplysia brasiliana, whose geographic distribution does not overlap that of A. californica. This finding suggests that other mollusks release attractin-related pheromones to form and maintain breeding aggregations. We describe four additional members of the attractin family: A. brasiliana, Aplysia fasciata, Aplysia depilans (which aggregates with A. fasciata aggregations), and Aplysia vaccaria (which aggregates with A. californica aggregations). On the basis of their sequence similarity with A. californica attractin, the attractin proteins fall into two groups: A. californica, A. brasiliana, and A. fasciata (91-95% identity), and A. depilans and A. vaccaria (41-43% identity). The sequence similarity within the attractin family, the conserved six cysteines, and the compact fold of the NMR solution structure of A. californica attractin suggest a common fold for this pheromone family containing two antiparallel helices. The second helix contains the IEECKTS sequence conserved in Aplysia attractins. Mutating surface-exposed charged residues within this heptapeptide sequence abolishes attractin activity, suggesting that the second helix is an essential part of the receptor-binding interface.

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Peptide and protein pheromones in amphibians

Cited by 64 publications

References 17 publications

Characterization of Aplysia Enticin and Temptin, Two Novel Water-borne Protein Pheromones That Act in Concert with Attractin to Stimulate Mate Attraction

Characterization of Aplysia Enticin and Temptin, Two Novel Water-borne Protein Pheromones That Act in Concert with Attractin to Stimulate Mate Attraction

Evolutionary shifts in courtship pheromone composition revealed by EST analysis of plethodontid salamander mental glands

Structural and functional analysis of Aplysia attractins, a family of water-borne protein pheromones with interspecific attractiveness

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