DOI: 10.5061/dryad.g6bq21b
title: Data from: Elucidating the functional evolution of heat sensors among Xenopus species adapted to different thermal niches by ancestral sequence reconstruction

description: Ambient temperature fluctuations are detected via the thermosensory system
 which allows animals to seek preferable thermal conditions or escape from
 harmful temperatures. Evolutionary changes in thermal perception have thus
 potentially played crucial roles in niche selection. The genus Xenopus
 (clawed frog) is suitable for investigating the relationship between
 thermal perception and niche selection due to their diverse latitudinal
 and altitudinal distributions. Here we performed comparative analyses of
 the neuronal heat sensors TRPV1 and TRPA1 among closely related Xenopus
 species (X. borealis, X. muelleri, X. laevis, and X. tropicalis) to
 elucidate their functional evolution and to assess whether their
 functional differences correlate with thermal niche selection among the
 species. Comparison of TRPV1 among four extant Xenopus species and
 reconstruction of the ancestral TRPV1 revealed that TRPV1 responses to
 repeated heat stimulation were specifically altered in the lineage leading
 to X. tropicalis which inhabits warmer niches. Moreover, the thermal
 sensitivity of TRPA1 was lower in X. tropicalis than the other species,
 although the thermal sensitivity of TRPV1 and TRPA1 was not always lower
 in species that inhabit warmer niches than the species inhabit cooler
 niches. However, a clear correlation was found in species differences in
 TRPA1 activity. Heat-evoked activity of TRPA1 in X. borealis and X.
 laevis, which are adapted to cooler niches, was significantly higher than
 in X. tropicalis and X. muelleri which are adapted to warmer niches. These
 findings suggest that the functional properties of heat sensors changed
 during Xenopus evolution, potentially altering the preferred temperature
 ranges among species.
description: Data for Fig 2 &
 Fig3a-cElectrophysiological
 data used for Fig 2 and Fig 3a-c. The file include data for current
 amplitudes and normalized responses obtained by repeated heat stimulation
 (five times) from Xenopus laevis oocytes expressing TRPV1 from extant and
 ancestral clawed frog species. A basal current amplitude was obtained in a
 five-second duration just before each heat stimulation. If the maximum
 current amplitude was smaller than 0.5 μA, the current data obtained from
 such oocytes was excluded from analysis since we could not precisely judge
 the responses of TRPV1 to repeated heat stimulation.Data for
 Fig2&Fig3a-c.xlsxData for Fig
 3eThermal activation
 thresholds estimated by an Arrhenius plot using data obtained from Xenopus
 laevis oocytes expressing TRPV1 from extant and ancestral clawed frog
 species. The data for currents and temperatures were obtained at the first
 heat stimulation from Xenopus laevis oocytes expressing TRPV1 from extant
 and ancestral clawed frog species. Then, Arrhenius plots were performed as
 shown in Fig S2.Data for
 Fig3e.xlsxData for Fig
 5cThermal activation
 thresholds estimated by an Arrhenius plot using data obtained from Xenopus
 laevis oocytes expressing TRPA1 from Xenopus species. The data for
 currents and temperatures were obtained at the first heat stimulation from
 Xenopus laevis oocytes expressing TRPA1 from Xenopus species. Then,
 Arrhenius plots were performed as shown in Fig S5.Data for
 Fig5c.xlsxData for Fig 5d &
 5eElectrophysiological
 data used for Fig 5d & 5e. The file include data for current
 amplitudes and normalized responses obtained by heat stimulation, then 0.3
 mM cinnamaldehyde stimulation from Xenopus laevis oocytes expressing TRPA1
 from Xenopus species. A basal current amplitude was obtained in a
 five-second duration just before each stimulation. The current amplitude
 elicited by heat stimulation was normalized to that elicited by 0.3 mM
 cinnamaldehyde stimulation. Dose-dependent responses for Xbo-TRPA1a and
 Xmu-TRPA1a were obtained by applying different concentrations of
 cinnamaldehyde (0.01, 0.3, 1, and 2 mM) to Xenopus laevis oocytes
 expressing TRPA1a from each species. 2 mM cinnamaldehyde was applied to
 oocytes at the last in all the case to normalize current amplitudes evoked
 by lower concentrations of cinnamaldehyde.Data for
 Fig5d&e.xlsxData for Fig
 6Electrophysiological
 data used for Fig 6. The file include data for current amplitudes and
 normalized responses obtained by heat stimulation, then 0.3 mM
 cinnamaldehyde stimulation from Xenopus laevis oocytes expressing TRPA1a
 or TRPA1b from Xenopus laevis. Basal current amplitudes were obtained in a
 five-second duration just before each stimulation. The current amplitude
 elicited by heat stimulation was normalized to that elicited by 0.3 mM
 cinnamaldehyde stimulation. Dose-dependent responses for TRPA1a or TRPA1b
 from Xenopus laevis were obtained by applying different concentrations of
 cinnamaldehyde (0.01, 0.3, 1, and 2 mM) to Xenopus laevis oocytes
 expressing TRPA1a or TRPA1b. 2 mM cinnamaldehyde was applied to oocytes at
 the last in all the case to normalize current amplitudes evoked by lower
 concentrations of cinnamaldehyde.Data for
 Fig6.xlsxNucleotide sequences for
 Xenopus TRPV1Aligned nucleotide
 sequences for TRPV1 from extant and ancestral clawed frog
 species.Nucleotide sequences for
 Xenopus TRPA1Aligned nucleotide
 sequences for TRPA1 from Xenopus species.