Nephron localization of Na/SO4(2-)-cotransport-related mRNA and protein.
A Na+/SO4(2-)-cotransport system was recently identified from a rat kidney cortex cDNA library by expression cloning (NaSi-1;). In this work the sites of expression of NaSi-1-related mRNA and protein were determined using reverse transcriptase-polymerase chain reaction (RT-PCR) with microdissected nephron segments, and Western blot analysis on isolated tubules or purified membranes using polyclonal antibodies against the C-terminus of NaSi-1. Expression of both NaSi-1-related mRNA and protein was observed in proximal tubules and in papillary collecting ducts. Membrane separation studies indicated that in proximal tubules the NaSi-1-related protein is expressed apically. The observed distribution patterns (together with the earlier functional analysis) of NaSi-1-related mRNA and protein suggest that the NaSi-1 protein is involved in proximal tubular brush-border membrane Na+/SO4(2-)-cotransport. The functional correlation of the observed expression of the NaSi-1-related protein in collecting ducts remains to be determined.
Custer
M
M
Institute of Physiology, University of Zürich-Irchel, Switzerland.
Murer
H
H
Biber
J
J
D000818:Animals; D015139:Blotting, Southern; D015153:Blotting, Western; D004586:Electrophoresis; D015870:Gene Expression; D017136:Ion Transport / Q000235:genetics*; D009399:Nephrons / Q000502:physiology*; D011506:Proteins; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000235:genetics*; D013431:Sulfates
D011506:Proteins; D012333:RNA, Messenger; D015222:Sodium Channels; D013431:Sulfates