Pflügers Archiv

, Volume 446, Issue 1, pp 106–115

Cloning, gene structure and dietary regulation of the type-IIc Na/Pi cotransporter in the mouse kidney

  • I. Ohkido
  • H. Segawa
  • R. Yanagida
  • M. Nakamura
  • K. Miyamoto
Ion Channels, Transporters

DOI: 10.1007/s00424-003-1010-6

Cite this article as:
Ohkido, I., Segawa, H., Yanagida, R. et al. Pflugers Arch - Eur J Physiol (2003) 446: 106. doi:10.1007/s00424-003-1010-6

Abstract

We have demonstrated previously that the type-IIc Na/Pi cotransporter is a growth-related renal Na/Pi cotransporter that is highly expressed in kidney of the weaning rat. In the present study, we investigated type-IIc Na/Pi cotransporter function further by cloning the mouse gene and characterizing the corresponding protein. The mouse type-IIc transporter amino acid sequence shows a high degree of similarity to the human (86%) and rat (95%) type-IIc Na/Pi-cotransporters. The mouse gene contained 14 exons and mapped to chromosome 2. The DNA sequence upstream from exon 1 is GC rich. The upstream region does not contain an apparent TATA box, but does contain two dietary Pi-responsive elements, which are potential binding sites for the transcription factor µE3 (TFE3). Microinjection of mouse type-IIc cRNA into Xenopus oocytes demonstrated sodium-dependent Pi cotransport activity. The affinity for Pi was about 200 µM in 100 mM Na. Feeding adult mice fed a low-Pi diet increased the expression of type-IIc protein in the apical membrane of renal proximal tubular cells. Hybrid depletion studies suggested that the type-IIc transporter contributes to about 30% of Na/Pi cotransport in the kidney of adult mice fed a low-Pi diet. The present study suggests that the type-IIc Na/Pi cotransporter is a functional of renal Pi transporter in adult mice fed a low-Pi diet.

Keywords

PhosphateTransporterWeaningRegulationProximal tubules

Copyright information

© Springer-Verlag  2003

Authors and Affiliations

  • I. Ohkido
    • 1
    • 2
  • H. Segawa
    • 1
  • R. Yanagida
    • 1
  • M. Nakamura
    • 1
  • K. Miyamoto
    • 1
  1. 1.Department of Nutrition, School of MedicineTokushima UniversityTokushima CityJapan
  2. 2.Department of Internal Medicine, Division of Nephrology and HypertensionJikei University School of MedicineTokyoJapan