|ZFIN ID: ZDB-PUB-110131-15|
Functional and developmental expression of a zebrafish Kir1.1 (ROMK) potassium channel homologue Kcnj1
Abbas, L., Hajihashemi, S., Stead, L.F., Cooper, G.J., Ware, T.L., Munsey, T.S., Whitfield, T.T., and White, S.J.
|Source:||The Journal of physiology 589(Pt 6): 1489-503 (Journal)|
|Registered Authors:||Abbas, Leila, Whitfield, Tanya T.|
|Keywords:||Epithelial transport, Potassium channel, Zebrafish|
|PubMed:||21262879 Full text @ J. Physiol.|
Abbas, L., Hajihashemi, S., Stead, L.F., Cooper, G.J., Ware, T.L., Munsey, T.S., Whitfield, T.T., and White, S.J. (2011) Functional and developmental expression of a zebrafish Kir1.1 (ROMK) potassium channel homologue Kcnj1. The Journal of physiology. 589(Pt 6):1489-503.
ABSTRACTThe zebrafish, Danio rerio, is emerging as an important model organism for the pathophysiological study of a number of some human kidney diseases, but the sites of expression and physiological roles of a number of protein orthologues in the zebrafish nephron remain mostly undefined. Here we show that a zebrafish potassium channel is orthologous to the mammalian kidney potassium channel, ROMK . The cDNA (kcnj1) encodes a protein (Kcnj1) that when expressed in Xenopus laevis oocytes displayed pH - and Ba2+-sensitive K+-selective currents, but unlike the mammalian channel, was completely insensitive to the peptide inhibitor tertiapin-Q. In the pronephros, kcnj1 transcript expression was restricted to a distal region and overlapped with that of NKCC2, ClC-Ka and Barttin, indicating the location of the diluting segment. In a subpopulation of surface cells, kcnj1 was coexpressed with the a1a.4isoform of the Na+/K+-ATPase identifying these cells as potential K+ secretory cells in this epithelium. At later stages of development, kcnj1 appeared in cells of the developing gill that also expressed the a1a.4subunit. Morpholinoantisense-mediated knock down of kcnj1 was accompanied by transient tachycardia followed by bradycardia, effects consistent with alterations in extracellular K+ concentration in the embryo. Our findings indicate that Kcnj1 is expressed in cells associated with osmoregulation and acts as a K+ efflux pathway that is important in maintaining extracellular levels of K+ in the developing embryo.