The discovery of a novel sodium channel in the cockroach Periplaneta americana: Evidence for an early duplication of the para-like gene

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• 作者：Bé ; né ; dicte Moignot ; Christophe Lemaire ; Sophie Quinchard ; Bruno Lapied ; Christian Legros
• 关键词：Ion channels ; Insect ; Molecular cloning ; Phylogeny ; Sodium channels
• 刊名：Insect Biochemistry and Molecular Biology
• 出版年：2009
• 出版时间：November 2009
• 年：2009
• 卷：39
• 期：11
• 页码：814-823
• 全文大小：2053 K

文摘

Voltage-gated sodium channels (Na_v channels) belong to a superfamily of ion channels which play an essential role in membrane excitability. Only one gene encoding Na_v channels has been characterized so far in insects. Here, we have cloned one full-length cDNA encoding a conventional insect Na_v channel (PaNa_v1) and two full-length cDNAs encoding putative insect Na_v channels (PaFPC1 and PaFPC2) in Periplaneta americana, a model insect for neurophysiological studies. The ORFs of PaFPC1 and PaFPC2 contained 4662 bp and encoded 1553 amino acid residues, and the ORF of PaNa_v1 contained 6153 bp and encoded 2051 amino acid residues. PaFPC1 and PaFPC2 are two isoforms, which differ by eight single amino acid substitutions. PaFPC1 shares 37.5–55 % protein identities with known insect Na_v channels, while PaNa_v1 shares 70–97.5 % protein identities with these latter. Both PaFPC1 and PaFPC2 possess the molecular hallmarks of Na_v channels except the motif involved in fast inactivation. Contrary to PaNa_v1 transcripts which are expressed mainly in the central nervous system, those ones of PaFPC are also expressed in non-neuronal tissues (muscles, gut and mushroom-shaped accessory glands). A detailed phylogenetic analysis confirmed that PaNa_v1 and PaFPC are evolutionarily closely related to insect Na_v channel genes.