Fig 1.
Responses of feline bitter taste receptors to bitter compounds.
HEK293 cells transiently transfected with one of the feline Tas2r bitter receptors (Tas2r2, Tas2r4, Tas2r7, Tas2r12, Tas2r38, Tas2r46, or Tas2r67), with Gα16-gust44, were assayed for their responses to 25 bitter compounds. Black traces, calcium mobilization of seven feline bitter receptors to bitter compounds; grey traces, those of mock transfected cells used as control.
Fig 2.
Quantitative analysis of responses of feline bitter receptors to bitter compounds.
HEK293 cells were transiently transfected with a feline bitter receptor (Tas2r2, Tas2r4, Tas2r7, Tas2r12, Tas2r38, Tas2r46, or Tas2r67), with Gα16-gust44, and assayed for their responses to bitter compounds. Data are expressed as mean ± SE percent change in fluorescence (ΔF, peak fluorescence–baseline fluorescence) compared with baseline fluorescence (F) from three independent wells. Two-tailed Student’s t-tests were performed to determine when responses from Tas2r-transfected cells were significantly different from that of mock-transfect cells. Only bitter compounds that elicited significant responses above mock-transfected cell baseline are shown in the Figure.
Fig 3.
Feline Tas2rs respond to bitter compounds in a dose-dependent fashion.
HEK293 cells transiently transfected with feline Tas2rs with Gα16-gust44 showed dose-dependent responses to bitter compounds. Mock-transfected cells were used as controls. The data were fit by a sigmoidal function using GraphPad Prism 5.
Fig 4.
Phylogenetic tree of Tas2r repertoires of seven species in the order Carnivora.
Only the predicted intact Tas2r receptors are included. Sequences were either taken from Li and Zhang or obtained from reBLASTing genomes of these seven species. The tree was constructed by using the maximum-likelihood method based on the matrix-based model of [24] implemented in Mega 6 [25]. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site.
Table 1.
Tas2r repertoires in seven species within the order Carnivora and other aquatic mammals.
Table 2.
Presence of Tas2r genes in seven species in the order Carnivora.