Baumann A, Frings S, Godde M, Seifert R, Kaupp U B
Institut für Biologische Informationsverarbeitung, Forschungszentrum Jülich, Germany.
EMBO J. 1994 Nov 1;13(21):5040-50. doi: 10.1002/j.1460-2075.1994.tb06833.x.
Cyclic nucleotide-gated (CNG) ion channels serve as downstream targets of signalling pathways in vertebrate photoreceptors and olfactory sensory neurons. Whether CNG channels subserve similar functions in invertebrate photoreception and olfaction is unknown. We have cloned genomic DNA and cDNA encoding a cGMP-gated channel from Drosophila. The gene contains at least seven exons. Heterologous expression of cloned cDNA in both Xenopus oocytes and HEK 293 cells gives rise to functional ion channels. The Drosophila CNG channel is approximately 50-fold more sensitive to cGMP than to cAMP. The voltage dependence of blockage by divalent cations is different compared with the CNG channel of rod photoreceptors, and the Ca2+ permeability is much larger. The channel mRNA is expressed in antennae and the visual system of Drosophila. It is proposed that CNG channels are involved in transduction cascades of both invertebrate photoreceptors and olfactory sensillae.
环核苷酸门控（CNG）离子通道是脊椎动物光感受器和嗅觉感觉神经元信号通路的下游靶点。在无脊椎动物的光感受和嗅觉中，CNG通道是否发挥类似功能尚不清楚。我们已经克隆了果蝇中编码一种cGMP门控通道的基因组DNA和cDNA。该基因至少包含七个外显子。在非洲爪蟾卵母细胞和人胚肾293细胞中克隆cDNA的异源表达产生了功能性离子通道。果蝇CNG通道对cGMP的敏感性比对cAMP高约50倍。与视杆光感受器的CNG通道相比，二价阳离子阻断的电压依赖性不同，并且Ca2+通透性要大得多。该通道mRNA在果蝇的触角和视觉系统中表达。有人提出，CNG通道参与无脊椎动物光感受器和嗅觉感受器的转导级联反应。
