Characterization of two novel ammonia transporters, Hiat1a and Hiat1b, in the teleost model system Danio rerio.

Autor:	Zhouyao H; University of Manitoba, Department of Food and Human Nutritional Sciences, 66 Chancellors Circle, Winnipeg, MB, Canada, R3T 2N2., Zimmer AM; University of Alberta, Department of Biological Science, 11355 Saskatchewan Drive, Edmonton, AB, Canada, T6G 2E9.; University of Ottawa, Department of Biology, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5., Fehsenfeld S; Université du Quebec à Rimouski, Département de biologie, chimie et géographie, 300 Allée des Ursulines, Rimouski, QC, Canada, G5L 3A1., Liebenstein T; Universität Bayreuth, Department of Biology, Universitätsstr. 30, University of Bayreuth, 95440 Bayreuth, Germany., Richter DO; Universität Bayreuth, Department of Biology, Universitätsstr. 30, University of Bayreuth, 95440 Bayreuth, Germany., Begemann G; Universität Bayreuth, Department of Biology, Universitätsstr. 30, University of Bayreuth, 95440 Bayreuth, Germany., Eck P; University of Manitoba, Department of Food and Human Nutritional Sciences, 66 Chancellors Circle, Winnipeg, MB, Canada, R3T 2N2., Perry SF; University of Ottawa, Department of Biology, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5., Weihrauch D; University of Manitoba, Department of Biological Sciences, 66 Chancellors Circle, Winnipeg, MB, Canada, R3T 2N2.
Jazyk:	angličtina
Zdroj:	The Journal of experimental biology [J Exp Biol] 2022 Oct 15; Vol. 225 (20). Date of Electronic Publication: 2022 Oct 17.
DOI:	10.1242/jeb.244279
Abstrakt:	Ammonia excretion in fish excretory epithelia is a complex interplay of multiple membrane transport proteins and mechanisms. Using the model system of zebrafish (Danio rerio) larvae, here we identified three paralogues of a novel ammonia transporter, hippocampus-abundant transcript 1 (DrHiat1), also found in most vertebrates. When functionally expressed in Xenopus laevis oocytes, DrHiat1a and DrHiat1b promoted methylamine uptake in a competitive manner with ammonia. In situ hybridization experiments showed that both transporters were expressed as early as the 4-cell stage in zebrafish embryos and could be identified in most tissues 4 days post-fertilization. Larvae experiencing morpholino-mediated knockdown of DrHiat1b exhibited significantly lower whole-body ammonia excretion rates compared with control larvae. Markedly decreased site-specific total ammonia excretion of up to 85% was observed in both the pharyngeal region (site of developing gills) and the yolk sac (region shown to have the highest NH4+ flux). This study is the first to identify DrHiat1b/DrHIAT1 in particular as an important contributor to ammonia excretion in larval zebrafish. Being evolutionarily conserved, these proteins are likely involved in multiple other general ammonia-handling mechanisms, making them worthy candidates for future studies on nitrogen regulation in fishes and across the animal kingdom. Competing Interests: Competing interests The authors declare no competing or financial interests. (© 2022. Published by The Company of Biologists Ltd.)
Databáze:	MEDLINE
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