Authors: I Ohkido H Segawa R Yanagida M Nakamura K Miyamoto
Publish Date: 2003/02/25
Volume: 446, Issue: 1, Pages: 106-115
Abstract
We have demonstrated previously that the typeIIc Na/Pi cotransporter is a growthrelated renal Na/Pi cotransporter that is highly expressed in kidney of the weaning rat In the present study we investigated typeIIc Na/Pi cotransporter function further by cloning the mouse gene and characterizing the corresponding protein The mouse typeIIc transporter amino acid sequence shows a high degree of similarity to the human 86 and rat 95 typeIIc Na/Picotransporters 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 Piresponsive elements which are potential binding sites for the transcription factor µE3 TFE3 Microinjection of mouse typeIIc cRNA into Xenopus oocytes demonstrated sodiumdependent Pi cotransport activity The affinity for Pi was about 200 µM in 100 mM Na Feeding adult mice fed a lowPi diet increased the expression of typeIIc protein in the apical membrane of renal proximal tubular cells Hybrid depletion studies suggested that the typeIIc transporter contributes to about 30 of Na/Pi cotransport in the kidney of adult mice fed a lowPi diet The present study suggests that the typeIIc Na/Pi cotransporter is a functional of renal Pi transporter in adult mice fed a lowPi dietThis work was supported by Grant 11557202 KM from the Ministry of Education Science Sports and Culture of Japan We thank Kayo Yano Ritsuko Saito Keiko Shinohara Noriko Yata and Ichiro Kaneko The mouse osteoclast mRNA were a kind gift from Dr Amano Showa University Tokyo Japan The nucleotide sequences reported in this paper have been submitted to the GenBank/EBI Data Bank with accession numbers AB054999 and AB080121AB080134
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