title: Expression of a renal Na(+)-nucleoside cotransport system (N2) in Xenopus laevis oocytes.
abstract: Xenopus laevis oocytes have been used for the expression of a renal, pyrimidine-selective, Na(+)-nucleoside cotransporter (N2). As compared to its uptake in water-injected oocytes, Na(+)-dependent thymidine uptake was enhanced in a time- and dose-dependent manner in oocytes injected with rat renal cortex total poly(A)+ RNA. An increased uptake was also observed after injection of size fractionated rat renal cortex poly(A)+ RNA (2-3 kb). Consistent with the selectivity of the N2 nucleoside transporter, cytidine significantly inhibited Na(+)-dependent thymidine uptake in oocytes injected with total poly(A)+ RNA whereas guanosine and formycin B did not. Na(+)-dependent thymidine uptake was also enhanced in oocytes injected with size fractionated human renal cortex poly(A)+ RNA (2-3 kb). The above data demonstrate functional expression of renal cortex, Na(+)-nucleoside cotransporters in Xenopus laevis oocytes.
authors.affiliation: School of Pharmacy, University of California, San Francisco 94143.
authors.forename: K M
authors.initials: KM
authors.lastname: Giacomini
authors.forename: D
authors.initials: D
authors.lastname: Markovich
authors.forename: A
authors.initials: A
authors.lastname: Werner
authors.forename: J
authors.initials: J
authors.lastname: Biber
authors.forename: X
authors.initials: X
authors.lastname: Wu
authors.forename: H
authors.initials: H
authors.lastname: Murer
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D017136:Ion Transport; D007672:Kidney Cortex / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism*; D011061:Poly A; D012313:RNA; D012333:RNA, Messenger; D012964:Sodium / Q000378:metabolism*; D027981:Symporters; D013936:Thymidine / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D002352:Carrier Proteins; D012333:RNA, Messenger; D027981:Symporters; C073034:sodium-nucleoside cotransporter; D011061:Poly A; D012313:RNA; D012964:Sodium; D013936:Thymidine