红藻氨酸和GABA受体在中华大蟾蜍卵母细胞的表达

本文报道了利用中华大蟾蜍卵母细胞作为外源性膜蛋白的表达及其功能特性研究的模式系统。将大鼠脑的mRNA微量注入蟾蜍卵母细胞(每个卵母细胞注射50ng),在19℃下经48h以上培养后,由外源mRNA表达的大鼠脑的红藻氨酸和γ-氨基丁酸受体被整合到了卵母细胞膜上。红藻氨酸(5×10~(-5)mol/L)和γ-氨基丁酸(10~(-4)mol/L)所诱导的膜电流分别达到294.0±6.4nA(n=5)和309.5±4.9nA(n=4)。红藻氨酸浓度在10~(-3)mol/L时,其诱导的膜电流达最大值。进而,注射mRNA的卵母细胞,~(36)Cl~-流入速度比对照组高一倍多。这些结果表明,中华大蟾蜍卵母细胞,如同爪蟾卵母细胞一样,能表达具有功能的外源膜蛋白(受体蛋白和离子运输蛋白)。

THE EXPRESSION OF KAINATE AND GABA RECEPTORS IN OOCYTES OF BUFO BUFO GARGARIZANS

Oocytes of Bufo bufo gargarizans were used as an expression system for analyzing structure of exogenous membrane protein and their functions. Poly (A)+ mRNA isolated from rat brain was injected into Toad (Bufo bufo gargarizans) oocytes (50 ng/oocyte). Rat brain kainic acid and gamma-aminobutyric acid(GABA) receptors expressed by the injected mRNA were integrated in the oocyte membrane 48 h after the injection at 19 degrees C. Membrane currents induced by kainic acid (5 x 10(-5) mol/L) and GABA (10(-4) mol/L) were 294.0 +/- 6.4 nA (n = 5) and 309.5 +/- 4.9 nA (n = 4) respectively. The kainic acid induced current reached its maximum value at about 10(-3) mol/L. Moreover, it was observed that the 36Cl- influx of the oocytes microinjected with mRNA was one-fold more rapid than the control oocytes. These results indicate that the oocytes of Bufo bufo gargarizans as those of Xenopus laevis can be used to express membrane proteins (receptors & transports) to acquire their proper functions from exogenous mRNA.