双孔钾离子通道TREK-1功能性串联二聚体载体的构建

Construction of functional and concatenated dimers of two-pore-domain potassium channel TREK-1

目的 探讨在双孔钾离子通道（K2P）TREK-1（TWIK related K^＋channel 1）分子间加入柔性linker构建串联二聚体载体的可行性。方法 利用PCR技术在两个单体TREK-1分子之间加入一个linker,构建串联二聚体载体（p GH19-td TREK-1）。将上述载体体外转录成cRNA并显微注射至爪蟾卵母细胞,培养24~48 h后采用双电极电压钳技术记录电流。观察胞外钡离子和不同p H值外液对该串联二聚体通道表达的影响,并与天然二聚体通道的反应相比较。结果 串联二聚体Td TREK-1可在爪蟾卵母细胞中高效表达,该通道形成的电流可被胞外钡离子抑制,也可被胞外液酸化所抑制,而该串联二聚体通道对这些胞外刺激因素的反应程度与天然二聚体相似。结论人为加入柔性linker序列构建串联二聚体TREK-1通道并不影响通道的表达及门控特性,证明该实验方案可行。这将为操作单个亚基,进而深入研究TREK-1的结构与功能打下良好的基础。

Objective To explore the feasibility of adding a flexible linker between two-pore-domain potassium channel TREK-1 （TWIK related K^＋ channel 1）monomers to construct a tandem-linked dimer.Methods PCR was used to add a flexible linker between the two TREK-1 monomers.The cRNA obtained from in vitro transcription using the above vector was injected into Xenopus oocytes.After 24 -48 h,currents were recorded from these oocytes using a two-electrode voltage clamp.The effects of extracellular Ba2 ＋ and pH on TdTREK-1 were observed and compared with those of native dimeric TREK-1.Results The tandem-linked dimeric TdTREK-1 was highly expressed in Xenopus oocytes.The currents through these channels were inhibited by extracellular Ba^2 ＋and acidification.Furthermore,the responsiveness of the concatenated dimers to these extracellular stimuli was similar to that of native dimers.Conclusion Adding a flexible linker between the two monomers to construct the tandem-linked dimer does not affect the expression and gating properties of TREK-1, suggesting that the method be feasible.Such a method will allow the manipulation of a single subunit,which will help basis study the structure and function of TREK-1.