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. Author manuscript; available in PMC: 2021 Nov 1.
Published in final edited form as: FASEB J. 2020 Sep 12;34(11):14850–14862. doi: 10.1096/fj.201902308RR

Figure 4. Pancreatic expression of the zebrafish orthologue of the 12-HETE receptor gpr31.

Figure 4.

(A) Phylogenetic relationship among GPR31 orthologues in Homo sapiens, Danio rerio (fish), Mus musculus (mouse), and Rattus norvegicus (rat) and the closely related G protein coupled receptor LTB4R2 generated by Clustal Omega analysis of peptide sequences. Zebrafish Gpr31 clusters together with the mammalian homologues. (B) Quantitative PCR analysis showing expression levels of gpr31 mRNA at embryonic stages from 1 dpf through 4 dpf. Levels are depicted as relative to the ubiquitously expressed gene elfa and were normalized to the relative expression level at 1 dpf. Global expression of gpr31 peaks at 2 dpf. (C-C’’) Merged (C), single channel (C’), and single channel inset (C’’) confocal image of 3 dpf Tg(ptf1a:GFP)jh1 transgenic embryo with expression of gpr31 marked by fluorescent whole mount in situ hybridization (red). Signal for gpr31 is detected throughout the green fluorescent pancreatic region (p). DNA is marked by TOPRO-3 (blue). (D,E) Tg(ptf1a:GFP)jh1 zebrafish embryos injected with 0 ng (D) or 2 ng (E) of gpr31 antisense morpholino as zygotes; shown at 3 dpf. (D) Control embryo shows GFP expression (green) in the exocrine pancreas (xp), hindbrain (hb), and retina (rt) (E) zebrafish injected with 2 ng gpr31MO show a severe shortened pancreas phenotype. (F) Quantification of GFP+ exocrine pancreas length shows an impressive and highly significant shortening of 63.6% (p < 0.0001). Lipidomic analysis of LOX products from 3 3dpf embryos injected with 2mg Gpr31 MO. (I) 12-LOX products from Gpr31 MO, 12-HETE, 12-HEPE, 14-HDHA and 8-HETE, no significant difference (t-test, p = > 0.05). (J) 15-LOX products from Gpr31 MO, 15-HETE, 15-HEPE and 13-HODE; no significant difference (t-test, p = > 0.05). 17-HDHA non detectable (K) 5-LOX products from Gpr31 MO, 5-HETE, no significant difference (t-test, p = > 0.05). 5-HEPE, 9-HODE and 4-HDHA non detectable.