title: Expression of acid-sensing ion channels and selection of reference genes in mouse and naked mole rat.
abstract: Acid-sensing ion channels (ASICs) are a family of ion channels comprised of six subunits encoded by four genes and they are expressed throughout the peripheral and central nervous systems. ASICs have been implicated in a wide range of physiological and pathophysiological processes: pain, breathing, synaptic plasticity and excitotoxicity. Unlike mice and humans, naked mole-rats do not perceive acid as a noxious stimulus, even though their sensory neurons express functional ASICs, likely an adaptation to living in a hypercapnic subterranean environment. Previous studies of ASIC expression in the mammalian nervous system have often not examined all subunits, or have failed to adequately quantify expression between tissues; to date there has been no attempt to determine ASIC expression in the central nervous system of the naked mole-rat. Here we perform a geNorm study to identify reliable housekeeping genes in both mouse and naked mole-rat and then use quantitative real-time PCR to estimate the relative amounts of ASIC transcripts in different tissues of both species. We identify RPL13A (ribosomal protein L13A) and CANX (calnexin), and β-ACTIN and EIF4A (eukaryotic initiation factor 4a) as being the most stably expressed housekeeping genes in mouse and naked mole-rat, respectively. In both species, ASIC3 was most highly expressed in dorsal root ganglia (DRG), and ASIC1a, ASIC2b and ASIC3 were more highly expressed across all brain regions compared to the other subunits. We also show that ASIC4, a proton-insensitive subunit of relatively unknown function, was highly expressed in all mouse tissues apart from DRG and hippocampus, but was by contrast the lowliest expressed ASIC in all naked mole-rat tissues.
authors.affiliation: Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK.|Department of Cell & Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
authors.forename: Laura-Nadine
authors.initials: LN
authors.lastname: Schuhmacher
authors.affiliation: Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK. es336@cam.ac.uk.
authors.forename: Ewan St John
authors.initials: ES
authors.lastname: Smith
mesh_terms: D062565:Acid Sensing Ion Channels / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D005260:Female; D008297:Male; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D019577:Mole Rats; D009928:Organ Specificity / Q000235:genetics; D012313:RNA / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000592:standards*; D012015:Reference Standards; D012984:Software
chemical_list: D062565:Acid Sensing Ion Channels; D012313:RNA
keywords: Acid-sensing ion channel; Central nervous system; Comparative study; Gene expression; Housekeeping gene selection; Naked mole-rat; Normalization; Quantitative real-time PCR; geNorm