Fig 4

Olfactory response to bile acid is reduced in foxj1 mutant zebrafish larvae.

(A) Schematic of the olfactory experiment, showing a 4-dpf zebrafish larva embedded in agarose. Its nose was exposed, and odor stimuli were delivered by a fine tube. (B) Neural activity was measured using the Ca²⁺-reporter GCaMP6s (Tg(elavl3:Gcamp6s)) in a region of interest spanning the entire OE. (C, C’) Representative example showing neural activity in the OE and OB to various odor types. Note that responses in the OB were spatially organized, with nonoverlapping domains. (D-D””) Averaged traces of neural activity on the OE for foxj1b control (n = 12) and mutant (n = 8) fish for each odor type showed no difference in odor responses. Maximum amplitude is shown in the insets. (E-E””) Averaged traces of neural activity in the OE for control (n = 7), foxj1a mutant (n = 10), and double foxj1a/b mutant (n = 14) showed a significant reduction in bile acid response. Shaded error bars are standard error of the mean. Maximum amplitude and standard deviation are shown in the insets. Significance identified by two-sample t test, *: p < 0.05, **: p < 0.01. Raw data files and codes for analysis are available in Mendeley Data (https://data.mendeley.com/datasets/2pn963jn6y). a, anterior; AA, amino acid; BA, bile acid; dpf, days post fertilization; FO, food odor; NU, nucleic acid; OB, olfactory bulb; OE, olfactory epithelium; p, posterior.