Expression of size-selected messenger RNA encoding the brain and adrenal gland angiotensin-II receptor in Xenopus laevis oocytes.

The expression of the rat angiotensin-II receptor has been studied in Xenopus oocytes. Poly(A)+ RNA isolated from the brain and adrenal gland was injected into oocytes, and the expression of the receptor in the oocyte plasma membrane was assayed by measuring the change in membrane potential in the presence of angiotensin-II. Expression of the angiotensin-II receptor was detected 1.0-1.5 days after messenger RNA (mRNA) injection, and the degree of membrane depolarization was proportional to the amount of mRNA injected. Ca+2 channel blockers inhibited the angiotensin-II-induced depolarization. The total mRNA was fractionated by preparative agarose gel electrophoresis and each fraction was assayed for its ability to induce angiotensin-II depolarization. The mRNA encoding the angiotensin-II receptor was found in a single fraction of 4.4 kilobases.