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Fig. S1
Expression patterns of taste bud markers used in this study. A-C: Expression of tg(tph1b:mCherry) in the developing oropharyngeal 5-HT cells. Anterior to the left. 1µm confocal optic section showing cells co-expressing tg(tph1b:mCherry) and 5-HT in the oropharynx of an embryo processed for immunohistochemistry with anti-mCherry and anti-5-HT antibodies. Within the white dotted-line oval are located the 5-HT cells of the mouth; otherwise, 5-HT cells located on anterior pharyngeal arches. D-I: Expression of zebrafish plcβ2 and Calb2 in taste bud tg(Ola.plcβ2:egfp) expressing cells. Anterior to the top. 5µm confocal optic sections in the mouth area, showing cells co-expressing tg(Ola.plcβ2:egfp) (E,H, green, anti- GFP) and plcβ2 mRNA (D, red, cRNA probe) or Calb2 (G, red, anti-Calb2), in the oropharynx of two zebrafish larvae. J: fgf8a mRNA is expressed in taste bud cells. To validate the tg(fgf8a.dr17:gfp) line as a tool for taste bud development, we checked whether fgf8a mRNA expression persists in developing taste bud cells and not only expressed in the oropharyngeal epithelium as previously shown (Kapsimali et al., 2011). 2µm optic section showing fgf8a mRNA (fast red fluorescent signal) in taste-bud cells detected by transmission light. K: Normal distribution of the distance (µm) between neighbouring taste buds in the wild-type mouth epithelium at 5dpf. Mean value=89µm, sd=34µm, n=87 pairs from 9 larvae. Shapiro-Wilk normality test : W = 0.9809, pvalue = 0.2217. L: Top: Cartoon showing the changing position of the mouth during the developmental period we performed imaging. The mouth is displaced from ventral (shown in the slightly oblique larval head schema at 60hpf) to dorsal and anterior position. The epithelium surrounding the mouth opening is coloured in green and we imaged the anterior part of it. Bottom: Schema of a forming taste bud. The dotted line shows the levels of zoptical sections in Fig.1 and S1. M: Cartoon showing the (co-) expression of taste bud cell markers during developmental timing (hours or days post fertilization) in the zebrafish anterior mouth. This study focused on tools required to observe early differentiating (tg(fgf8a.dr17:gfp) referred also as ‘fgf8a’ for clarity, 5-HT (Type-III), or Type-II (Calb2, plcb2) cells (black-lined rectangle). Markers for the same cell type, are shown in the same colour. The coloured lines indicate expression throughout this developmental time-period.