Functional differences among alternatively spliced variants of Slowpoke, a Drosophila calcium-activated potassium channel.
Functional differences among alternatively spliced variants of Slowpoke, a Drosophila calcium-activated potassium channel.
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发表时间：
1994-08
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通讯作者：
A. Lagrutta;Ke-Zhong Shen;R. North;John P. Adelman
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作者：
A. Lagrutta;Ke-Zhong Shen;R. North;John P. Adelman
果蝇的Slowpoke基因座编码一个可变剪接的mRNA家族，该家族编码大电导钙激活钾通道。氨基酸块中的可变性残基指定为框A、C、E、G和I。卵母细胞注射cRNA，所述cRNA已被选择用于单盒差异的直接功能比较。单通道记录从内到外补丁的卵母细胞膜表达A1或A3形式，E1或E2形式，和G2-G5形式进行了分析和比较。A1和A3之间的主要功能差异在于单位电导，而E1和E2之间的主要性质差异在于钙敏感性。活化动力学在G3和G5之间是不同的，但在不同的A盒和E盒背景中并不一致。结果表明，一个共同的RNA前体的选择性剪接有助于表达通道的功能多样性。我们的研究结果表明，慢波通道亚基的可变区包括模块化的，但相互作用的功能域，影响单位电导，钙敏感性和门控的基本特征。
The Slowpoke locus of Drosophila melanogaster encodes a family of alternatively spliced mRNAs which encode large conductance calcium-activated potassium channels. Variability residues in blocks of amino acids designated boxes A, C, E, G, and I. Oocytes were injected with cRNAs that had been chosen for direct functional comparison of single box differences. Single channel records from inside-out patches of oocyte membranes expressing A1 or A3 forms, E1 or E2 forms, and G2-G5 forms were analyzed and compared. The main functional difference between A1 and A3 was in unitary conductance, whereas the main difference in properties between E1 and E2 was in calcium sensitivity. Activation kinetics were different between G3 and G5, but not consistently in different A and E box backgrounds. The results indicate that alternative splicing of a common RNA precursor contributes to the functional diversity of the expressed channel. Our findings suggest that the variable region of the Slowpoke channel subunit comprises modular, yet interactive functional domains which influence the essential features of unit conductance, calcium sensitivity, and gating.