Expression of Na/Pi cotransport from opossum kidney cells in Xenopus laevis oocytes.
Xenopus laevis oocytes have been used for the expression of Na/Pi-cotransport activity by injections of poly(A)+ RNA (mRNA) isolated from an established renal cell line (OK cells). 3-5 days after mRNA injection, Na-dependent phosphate (Pi) uptake by oocytes was increased in a dose-dependent manner; there was no increase in Na-independent Pi uptake. Sucrose density-gradient fractionation indicated that the mRNA species encoding this activity is 2.4-2.8 kb in length. In Northern blots, using a cDNA probe related to human kidney-cortex Na/Pi-cotransport activity (NaPi-3), hybridization with a mRNA-species of 2.4-2.6 kb was obtained. Kinetic characterization ([Pi], [Na]) showed that expressed transport activity has properties similar to apical Na/Pi cotransport in OK cells.
Sorribas
V
V
Institute of Physiology, University of Zürich, Switzerland.
Markovich
D
D
Werner
A
A
Biber
J
J
Murer
H
H
D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D007668:Kidney / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000378:metabolism; D007700:Kinetics; D009693:Nucleic Acid Hybridization; D009865:Oocytes; D009893:Opossums; D010710:Phosphates / Q000378:metabolism*; D011061:Poly A / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis; D012964:Sodium / Q000378:metabolism*; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D014982:Xenopus laevis
D002352:Carrier Proteins; D010710:Phosphates; D012333:RNA, Messenger; D011994:Recombinant Proteins; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D011061:Poly A; D012964:Sodium