TY - JOUR
T1 - Anion exchanger 1b, but not sodium-bicarbonate cotransporter 1b, plays a role in transport functions of zebrafish H+-ATPase-rich cells
AU - Lee, Yi Chun
AU - Yan, Jia Jiun
AU - Cruz, Shelly A.
AU - Horng, Jiun Lin
AU - Hwang, Pung Pung
PY - 2011/2
Y1 - 2011/2
N2 - Similar to mammalian proximal tubular cells, H+-ATPase rich (HR) cells in zebrafish skin and gills are also responsible for Na+ uptake and acid secretion functions. However, the basolateral transport pathways in HR cells are still unclear. In the present study, we tested the hypothesis if there are specific slc4 members involved in basolateral ion transport pathways in HR cells. Fourteen isoforms were identified in the zebrafish(z) slc4 family, and the full-length cDNAs of two novel isoforms, zslc4a1b (anion exchanger, zAE1b) and zslc4a4b (Na+/HCO3
- cotransporter, zNBCe1b), were sequenced. mRNA signals of zslc4a1b and zslc4a4b were mainly detected in certain groups of ionocytes in zebrafish skin/gills. Further double immunocytochemistry or in situ hybridization demonstrated that zAE1b, but not zNBCe1b, was localized to basolateral membranes of HR cells. Acclimation to low-Na+ or acidic environments stimulated the mRNA expression of zslc4a1b in zebrafish gills, and loss-of-function of zslc4a1b with specific morpholinos caused significant decreases in both the whole body Na+ content and the skin H+ activity in the morphants. On the basis of these results, it was concluded that zAE1b, but not zNBCe1b, is involved in the basolateral transport pathways in Na+ uptake/acid secretion mechanisms in zebrafish HR cells.
AB - Similar to mammalian proximal tubular cells, H+-ATPase rich (HR) cells in zebrafish skin and gills are also responsible for Na+ uptake and acid secretion functions. However, the basolateral transport pathways in HR cells are still unclear. In the present study, we tested the hypothesis if there are specific slc4 members involved in basolateral ion transport pathways in HR cells. Fourteen isoforms were identified in the zebrafish(z) slc4 family, and the full-length cDNAs of two novel isoforms, zslc4a1b (anion exchanger, zAE1b) and zslc4a4b (Na+/HCO3
- cotransporter, zNBCe1b), were sequenced. mRNA signals of zslc4a1b and zslc4a4b were mainly detected in certain groups of ionocytes in zebrafish skin/gills. Further double immunocytochemistry or in situ hybridization demonstrated that zAE1b, but not zNBCe1b, was localized to basolateral membranes of HR cells. Acclimation to low-Na+ or acidic environments stimulated the mRNA expression of zslc4a1b in zebrafish gills, and loss-of-function of zslc4a1b with specific morpholinos caused significant decreases in both the whole body Na+ content and the skin H+ activity in the morphants. On the basis of these results, it was concluded that zAE1b, but not zNBCe1b, is involved in the basolateral transport pathways in Na+ uptake/acid secretion mechanisms in zebrafish HR cells.
KW - Acid-base regulation
KW - Fish
KW - Ion regulation
KW - Mitochondrion-rich cell
KW - Na uptake
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U2 - 10.1152/ajpcell.00263.2010
DO - 10.1152/ajpcell.00263.2010
M3 - Article
C2 - 21123736
AN - SCOPUS:79251564044
VL - 300
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6143
IS - 2
ER -