mRNA-induced expression of the cardiac Na+-Ca2+ exchanger in Xenopus oocytes.
Xenopus oocytes were injected with total mRNA isolated from hearts of 1-day-old chicks. After 5 days of incubation the follicular cell layers were removed and the oocytes were loaded with Na+ by incubation in hypertonic EGTA solution at 37 degrees C. The Na+-loaded oocytes accumulated 45Ca2+ from a Na+-free medium at a 3-18-fold higher rate than noninjected oocytes or oocytes injected with control solution containing no mRNA. Oocytes not subjected to the Na+-loading procedure showed no mRNA-dependent 45Ca2+ uptake. Size fractionation of the mRNA using sucrose density gradient centrifugation under denaturing conditions led to the identification of a 25 S fraction competent for induction of the Na+-Ca2+ exchange system.
Sigel
E
E
Institute of Pharmacology, University of Bern, Switzerland.
Baur
R
R
Porzig
H
H
Reuter
H
H
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002352:Carrier Proteins / Q000235:genetics*; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D007700:Kinetics; D008845:Microinjections; D009865:Oocytes / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D019831:Sodium-Calcium Exchanger; D014981:Xenopus
D002132:Calcium Radioisotopes; D002352:Carrier Proteins; D012333:RNA, Messenger; D019831:Sodium-Calcium Exchanger; D002118:Calcium