卵胞内微注射mRNA后胞膜上出现的新离子流

AN ION CURRENT EXPRESSION AFTER INTRACELLULAR MICROINJECTION OF mRNA IN THE XENOPUS OOCYTES

以胞内微注射技术向爪蟾卵内注射羊气管上皮细胞抽提的Poly(A)^+mRNA,以电压钳技术观察卵膜离子流的变化。注射前卵膜上主要有Ca^(2+),Cl^-,K^+和Na^+流,在高钙溶液(10Ca-ND96)中,瞬间的Ca^(2+)激活Cl^-流较大,此离子流可被9-羟蒽阻断。注射mRNA后在9-羟蒽存在的情况下,向浴槽加入1mmol/L 8-Br-cAMP后新出现一个电压敏感的离子流,使电流电压曲线的零电流电位向右移;但在注射去离子水组未见此离子流。表明羊气管上皮里含有cAMP敏感的离子通道,并可被移植到爪蟾卵膜上。

Xenopus oocytes were injected with Poly(A) + mRNA obtained from the sheep trachea epithelial cells. Macroscopic currents through voltage operated channels were recorded using voltage clamping technique when the endogenous calcium-dependent chloride current was blocked by 2 mmol / L anthracene-9-carboxylate. A 8-Br-cAMP sensitive membrane conductance was observed in the oocytes injected with mRNA but not in that injected with H2O. These results indicate that there is a cAMP sensitive ionic channel in the poly(A) + mRNA from the sheep trachea epithelial cells, which could be transplanted into the membrane of the Xenopus oocyte.