ZFIN ID: ZDB-PUB-071210-8
Zebrafish Ae2.2 encodes a second Slc4a2 anion exchanger
Shmukler, B.E., Clark, J.S., Hsu, A., Vandorpe, D.H., Stewart, A.K., Kurschat, C.E., Choe, S.K., Zhou, Y., Amigo, J., Paw, B.H., and Alper, S.L.
Date: 2008
Source: Am. J. Physiol. Regul. Integr. Comp. Physiol. 294(3): R1081-R1091 (Journal)
Registered Authors: Amigo, Julio, Paw, Barry, Zhou, Yi
Keywords: none
MeSH Terms: Amino Acid Sequence; Animals; Anion Transport Proteins/genetics*; Antiporters/genetics*; Chloride-Bicarbonate Antiporters (all 18) expand
PubMed: 18046018 Full text @ Am. J. Physiol. Regul. Integr. Comp. Physiol.
FIGURES   (current status)
ABSTRACT
The genome of zebrafish D. rerio encodes two unlinked genes equally closely related to the SLC4A2/AE2 anion exchanger genes of mammals. One of these is the recently reported zebrafish Ae2 gene (Shmukler et al., Am J Physiol Renal Physiol 289:R835, 2005), now called Ae2.1. We now report the structural and functional characterization of the second zebrafish AE2 gene product, Ae2.2. The Ae2.2 gene of zebrafish LG24 encodes a polypeptide of 1232 aa in length, sharing 70% amino acid identity with zebrafish Ae2.1 and 67% identity with mouse AE2a. Zebrafish Ae2.2 expressed in Xenopus oocytes encodes a 135 kDa polypeptide that mediates bidirectional, DIDS-sensitive Cl(-)/Cl(-) exchange and Cl(-)/HCO3(-) exchange. Ae2.2-mediated Cl(-)/Cl(-) exchange is cation-independent, voltage-insensitive, and electroneutral. Acute regulation of anion exchange mediated by Ae2.2 includes activation by NH4(+) and independent inhibition by acidic intracellular pH (pHi) and by acidic extracellular pH (pHo). In situ hybridization reveals low-level expression of Ae2.2 mRNA in zebrafish embryo, most notably in posterior tectum, eye, pharynx, epidermal cells, and axial vascular structures, without notable expression in the Ae2.1-expressing pronephric duct. Knockdown of Ae2.2 mRNA, of Ae2.1 mRNA, or of both with nontoxic levels of N-morpholino-oligomers produced no grossly detectable morphological phenotype, and preserved normal structure of the head and the pronephric duct at 24 hpf. Key words: Chloride/bicarbonate exchanger, Xenopus oocyte, isotopic flux, in situ hybridization, N-morpholino oligomer.
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