RRC ID 4133
Author Esaki M, Hoshijima K, Kobayashi S, Fukuda H, Kawakami K, Hirose S.
Title Visualization in zebrafish larvae of Na(+) uptake in mitochondria-rich cells whose differentiation is dependent on foxi3a.
Journal Am. J. Physiol. Regul. Integr. Comp. Physiol.
Abstract Uptake of Na(+) from the environment is an indispensable strategy for the survival of freshwater fish, as they easily lose Na(+) from the plasma to a diluted environment. Nevertheless, the location of and molecules involved in Na(+) uptake remain poorly understood. In this study, we utilized Sodium Green, a Na(+)-dependent fluorescent reagent, to provide direct evidence that Na(+) absorption takes place in a subset of the mitochondria-rich (MR) cells on the yolk sac surface of zebrafish larvae. Combined with immunohistochemistry, we revealed that the Na(+)-absorbing MR cells were exceptionally rich in vacuolar-type H(+)-ATPase (H(+)-ATPase) but moderately rich in Na(+)-K(+)-ATPase. We also addressed the function of foxi3a, a transcription factor that is specifically expressed in the H(+)-ATPase-rich MR cells. When foxi3a was depleted from zebrafish embryos by antisense morpholino oligonucleotide injection, differentiation of the MR cells was completely blocked and Na(+) influx was severely reduced, indicating that MR cells are the primary sites for Na(+) absorption. Additionally, foxi3a expression is initiated at the gastrula stage in the presumptive ectoderm; thus, we propose that foxi3a is a key gene in the control of MR cell differentiation. We also utilized a set of ion transport inhibitors to assess the molecules involved in the process and discuss the observations.
Volume 292(1)
Pages R470-80
Published 2007-1
DOI 10.1152/ajpregu.00200.2006
PII 00200.2006
PMID 16946087
MeSH Animals Calcium / physiology Cation Transport Proteins / antagonists & inhibitors Cell Differentiation / drug effects Hepatocyte Nuclear Factor 3-gamma / genetics* Image Processing, Computer-Assisted Immunohistochemistry In Situ Hybridization Larva / physiology* Mitochondria / metabolism* Morpholines / pharmacology Oligonucleotides, Antisense / pharmacology Organic Chemicals Proton-Translocating ATPases / metabolism Sodium / metabolism* Sodium Radioisotopes Sodium-Hydrogen Exchangers / metabolism Yolk Sac / cytology Yolk Sac / metabolism Zebrafish / physiology*
IF 3.176
Times Cited 82
Zebrafish ?