小鼠结肠平滑肌大电导钙激活钾通道的剪切与表达

目的检测小鼠结肠平滑肌大电导钙激活钾通道(large conductance calcium activated potassium channels,BKCa)mRNA的全长结构,探明该基因在结肠平滑肌的剪切形式,并对BKCaα亚基在消化道各节段的表达进行半定量比较。方法采用RT-PCR和Western blotting方法检测消化道各段平滑肌BKCa基因和蛋白的表达,用RT-PCR的方法分段检测小鼠结肠平滑肌上BKCa基因各个剪切位点的剪切形式。结果在小鼠无论在mRNA还是在蛋白水平,胃和结肠平滑肌BKCa的表达均比十二指肠、回肠部位丰富。结肠平滑肌上BKCaα亚基mRNA缺失第19号外显子即应激调控外显子(stress-regulated exon,STREX),在其他位点未检测到外显子剪切。结论在小鼠消化道各节段,结肠平滑肌上BKCa的含量比较高,其α亚基未表达第19号外显子序列,其表型为缺失应激调控外显子型,即ZERO型。

Splicing Variant and Expression of BKCa in Mice Colonic Smooth Muscle

Objective To investigate the whole length and the splicing variants of the large conductance calcium activated potassium channels(BKCa) mRNA in mice colonic smooth muscle, and the semi-quantify at BKCa α-subunit in various segments of gastrointestinal tract. Methods To observe the expression of BKCa α-subunit mRNA and protein in smooth muscle from various segments of gastrointestinal tract by RT PCR and Western blotting, and to examine the splice forms of all the splicing sites of BKCa mRNA in colonic smooth muscle by RT-PCR. Results The expressions of BKCa both at the mRNA and the protein levels, in the smooth muscles of mouse stomach and colon were more abundant than those in duodenum and ileum. Exon 19(stress-regulated exon, STREX) was spliced in the mRNA of BKCa α subunit in colonic smooth muscle while no splicing on other exons was detected. Conclusion The abundance of BKCa in colonic smooth muscle is high among the smooth muscles of the various gastrointestinal segments. The splicing variant BKCa in colonic smooth muscle was STREX lacking type, namely ZERO type.