Fig. 1

Expression of RL-TGR in zebrafish. (a) RT-qPCR analysis of rltgr in the early developmental stages of zebrafish, 3.5 hours post fertilization (hpf) to 7 days post fertilization (dpf). Gene expression was normalized to that of 18 S rRNA and presented as fold changes (mean ± SD) against 15 hpf expression. rltgr transcripts, which were detected by RT-qPCR analysis of whole embryos, begin to express from 8 hpf stage onwards. (b-b”) Whole mount in situ hybridization (WISH) showing the expression of rltgr at 7 dpf (dorsal, ventral, and lateral view, respectively). At 7 dpf, rltgr is expressed in both lateral as well as posterior part of pharyngeal region and intestine (b-b’, dorsal and ventral view, anterior to the top). Additionally, rltgr is expressed in the neuromasts of the lateral line system (black arrows, b”, lateral view, anterior to the left). (c–e’) Immunostaining of RL-TGR at 7 dpf in wild type embryos. RL-TGR-positive cells were detected (c-c’, dorsal view, anterior to the top) in the lips and neuromasts (white arrows) of the mouth region, (d-d’, ventral view, anterior to the top) neuromasts (white arrows) of the cephalic lateral line, and (e-e’, lateral view, anterior to the left) neuromasts (white arrows) of the posterior lateral line system. (f) Tissue specific expression of rltgr in adult zebrafish by RT-qPCR. Gene expression was normalized to that of 18 S rRNA and presented as fold changes (mean ± SD) against expression in muscle (4 biological replicates). The horizontal lines show median values. Corresponding to WISH results, the highest expression of rltgr was observed in the intestine followed by expression in muscles and mouth (upper and lower jaw). (f’) Image of adult zebrafish marking tissues analyzed for RT-qPCR in (f), adapted from Wikipedia commons³² with the license https://creativecommons.org/licenses/by/3.0/deed.en) (changed to grayscale). (g) Expression of rltgr in RNA Sequencing data of different tissues from independent studies available in short read archive database (SRA-NCBI). Read counts were normalized across the libraries for comparison. rltgr expression was observed in intestine, muscle, head and olfactory epithelium (OE). The different tissues of adult zebrafish harvested for total RNA extraction are depicted as a schematic diagram. (c–e’) are confocal single-plane images. n > 20 embryos; scale bars are shown in individual images.