果蝇光敏感通道TRP和TRPL的体内分析

In vivo analysis of the drosophila light-sensitive channels, TRP and TRPL.

作者信息

Reuss H, Mojet M H, Chyb S, Hardie R C

机构信息

Department of Anatomy, Cambridge University, United Kingdom.

出版信息

Neuron. 1997 Dec;19(6):1249-59. doi: 10.1016/s0896-6273(00)80416-x.

DOI:10.1016/s0896-6273(00)80416-x

PMID:9427248

Abstract

We have tested the proposal that the light-sensitive conductance in Drosophila is composed of two independent components by comparing the wild-type conductance with that in mutants lacking one or the other of the putative light-sensitive channel subunits, TRP and TRPL. For a wide range of cations, ionic permeability ratios in wild type were always intermediate between those of trp and trpl mutants. Effective channel conductances derived by noise analysis in wild type were again intermediate (17 pS; c.f. 35 pS in trp and 4 pS in trpl) and also showed a complex voltage dependence, which was quantitatively explained by the summation of TRPL and TRP channels after taking their different reversal potentials into account. Although La3+ partially blocked the light response in wild-type photoreceptors, it increased the effective single channel conductance. The results indicate that the wild-type light-activated conductance is composed of two separate channels, with the properties of TRP- and TRPL-dependent channels as determined in the respective mutants.

摘要

我们通过比较野生型电导与缺乏假定的光敏感通道亚基TRP和TRPL其中之一的突变体的电导，来检验果蝇中的光敏感电导由两个独立成分组成这一假说。对于多种阳离子而言，野生型中的离子渗透比总是介于trp和trpl突变体之间。通过噪声分析得出的野生型有效通道电导同样介于两者之间（17 pS；相比之下，trp为35 pS，trpl为4 pS），并且还表现出复杂的电压依赖性，在考虑到它们不同的反转电位后，TRPL和TRP通道的总和对其进行了定量解释。尽管La3+部分阻断了野生型光感受器中的光反应，但它增加了有效单通道电导。结果表明，野生型光激活电导由两个独立的通道组成，其特性与在各自突变体中确定的TRP依赖性和TRPL依赖性通道的特性一致。