目的 研究安氏隐孢子虫(Cryptosporidium andersoni)ATP结合盒式转运(ATP-binding cassette,ABC)蛋白1基因对细胞内液和细胞外液中K^+、Ca^2+、Na^+和Mg^2+的转运作用。 方法 设计特异性引物,从安氏隐孢子虫基因组中PCR扩增CaABC1。构建真核表达质粒pEGFP-C1-CaABC1,采用脂质体转染法将重组质粒转染至小鼠肠上皮细胞(intestinal epithelial cells,IEC)中表达,设空白组(未转染质粒组)、对照组(转染空质粒pEGFP-C1组)和转染组(转染重组质粒pEGFP-C1-CaABC1组)。用溶液离子浓度检测试剂盒检测 IEC细胞内液和细胞外液中的K^+、Ca^2+、Na^+和Mg^2+的浓度。 结果 扩增出544 bp的CaABC1基因,构建了真核表达质粒载体pEGFP-C1-CaABC1。转染小鼠IEC后,空白组未观察到绿色荧光,对照组和转染组均观察到绿色荧光。在细胞内液中,空白组K^+、Ca^2+、Na^+和 Mg^2+的浓度分别为(5.51±0.51)、(1.98±0.06)、(108.33±1.33)和(0.93±0.03)mmol/L,对照组分别为(6.25±0.70)、(1.90±0.13)、(107.73±1.79)和(0.87±0.05)mmol/L,转染组分别为(14.84±0.90)、(3.40±0.14)、(127.64±1.49)和(1.72±0.20)mmol/L。在细胞外液中,空白组K^+、Ca^2+、Na^+和Mg^2+的浓度分别为(12.72±0.83)、(3.72±0.03)、(116.83±1.04)和(2.02±0.18)mmol/L,对照组分别为(10.11±0.90)、(3.58±0.06)、(115.89±1.86)和(1.71±0.41)mmol/L,转染组分别为(5.77±0.21)、(1.29±0.18)、(96.21±1.19)和(0.64±0.02)mmol/L。转染组K^+、Ca^2+和Mg^2+与对照组相比,差异均有统计学意义(P〈0.05)。 结论 CaABC1蛋白具有协助转运K^+、Ca^2+和Mg^2+离子的作用。
Objective To investigate the transportation of intracellular and extracellular K^+, Ca^2+, Na^+ and Mg^2+ under the function of Cryptosporidium andersoni ATP-binding cassette(CaABC) 1 gene. Methods CaABC1 gene was amplified by PCR using specifically designed primers. The eukaryotic expression plasmid pEGFP-C1-CaABC1 was constructed, and transfected into mouse intestinal epithelial cells via liposome transfection. The blank(with no transfection) and control groups(transfected with empty plasmid pEGFP-C1) were also set. Changes in intracellular and extracellular K^+, Ca^2+, Na^+ and Mg^2+ concentrations were examined by the ion concentration assay kit. Results PCR amplification resulted in a 544 bp product. The recombinant plasmid pEGFP-C1-CaABC1 was successfully constructed. Green fluorescence was seen in the control and transfected groups, but not in the blank group. The concentrations of K^+, Ca^2+, Na^+ and Mg^2+ in intracellular fluid were (5.51 ± 0.51), (1.98 ± 0.06), (108.33 ± 1.33) and (0.93 ± 0.03) mmol/L in the blank group; (6.25 ± 0.70), (1.90 ± 0.13), (107.73 ± 1.79) and (0.87 ± 0.05) mmol/L in the control group; and (14.84 ± 0.90), (3.40 ± 0.14), (127.64 ± 1.49) and (1.72 ± 0.20) mmol/L in the transfected group. The concentrations of K^+, Ca^2+, Na^+ and Mg^2+ in extracellular fluid were (12.72 ± 0.83), (3.72 ± 0.03), (116.83 ± 1.04) and (2.02 ± 0.18) mmol/L in the blank group; (10.11 ± 0.90), (3.58 ± 0.06), (115.89 ± 1.86) and (1.71 ± 0.41) mmol/L in the control group; and (5.77 ± 0.21), (1.29 ± 0.18), (96.21 ± 1.19) and (0.64 ± 0.02) mmol/L in the transfected group. There were significant differences in K^+, Ca^2+ and Mg^2+ concentrations between the transfected group and the control group. Conclusion CaABC1 participates in the transportation of K^+, Ca^2+ and Mg^2+.