PUBLICATION
Functional characterization of a Na+-phosphate cotransporter (NaPi-II) from zebrafish and identification of related transcripts
- Authors
- Nalbant, P., Boehmer, C., Dehmelt, L., Wehner, F., and Werner, A.
- ID
- ZDB-PUB-991103-3
- Date
- 1999
- Source
- The Journal of physiology 520 Pt 1: 79-89 (Journal)
- Registered Authors
- Keywords
- none
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Base Sequence
- Carrier Proteins/genetics*
- Carrier Proteins/metabolism*
- Cloning, Molecular
- Electrophysiology
- Hydrogen-Ion Concentration
- Isomerism
- Kinetics
- Molecular Sequence Data
- Oocytes/metabolism
- Patch-Clamp Techniques
- Polymerase Chain Reaction
- Protein Conformation
- RNA, Antisense/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Sodium-Phosphate Cotransporter Proteins
- Sodium-Phosphate Cotransporter Proteins, Type IIb
- Symporters*
- Tissue Distribution
- Transcription, Genetic/genetics
- Xenopus laevis
- Zebrafish/physiology*
- Zebrafish Proteins
- PubMed
- 10517802 Full text @ J. Physiol.
Citation
Nalbant, P., Boehmer, C., Dehmelt, L., Wehner, F., and Werner, A. (1999) Functional characterization of a Na+-phosphate cotransporter (NaPi-II) from zebrafish and identification of related transcripts. The Journal of physiology. 520 Pt 1:79-89.
Abstract
1. We report the molecular identification of a Na+-Pi (inorganic phosphate) cotransport system of the NaPi-II protein family from zebrafish intestine. Following a PCR-related strategy, a DNA fragment from intestine-derived RNA was isolated. Rapid amplification of cDNA ends (3'- and 5'-RACE) resulted in the complete sequence (2607 bp) containing an open reading frame of 1893 bp. 2. The NaPi-II-related protein was expressed in Xenopus laevis oocytes and the resulting transport activity was analysed by electrophysiological means. The apparent Km for Pi was 250 muM (96 mM Na+, -60 mV), and voltage-dependent binding of Na+ exhibited a Km of 67.1 mM (1 mM Pi, -60 mV). 3. Interestingly, the overall transport activity was almost insensitive to changes in the holding potential. The apparent affinity for Na+ decreased under hyperpolarizing conditions, whereas Pi binding showed no voltage dependence. Transport activity was inhibited at low pH, which is characteristic for renal NaPi-II isoforms. 4. The expression of the NaPi-II-related isoform was addressed by reverse-transcription PCR. The mRNA
could be detected in intestine, liver, eye and kidney. Unexpectedly, a second NaPi-II-related isoform was identified and found to be expressed in kidney, intestine, liver, brain, eye and prominently in testis. In addition, a shorter amplicon was demonstrated to be an antisense transcript related to the NaPi-II intestinal isoform.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping