Expression pattern of the ether-a-go-go-related (ERG) family proteins in the adult mouse central nervous system: evidence for coassembly of different subunits.
Voltage-dependent K+ channels are the main determinants in controlling cellular excitability within the central nervous system. Among voltage-dependent K+ channels, the ERG subfamily is deeply involved in the control of cellular excitability, both in mammals and in invertebrates. ERG channels are encoded by different genes: the erg1 gene, which can generate two alternative transcripts (erg1a and erg1b), erg2 and erg3. The aim of the present study was to determine the expression pattern and cellular localization of ERG proteins (ERG1, ERG2, and ERG3) in the mouse CNS, differentiating, for the first time, the ERG1A and ERG1B isoforms. To this purpose, novel specific antibodies were raised against the various channel proteins and their specificity and immunoreactivity tested. It emerged that: 1) all the erg genes were indeed translated in neuronal tissue; 2) ERG proteins distribution in the mouse CNS often overlapped, and only in specific areas each ERG protein showed a distinct pattern of expression; and 3) ERG proteins were generally expressed in neuronal soma, but dendritic and/or white matter labeling could be detected in specific areas. The finding that ERG proteins often have an overlapping expression suggests that neuronal ERG currents could be determined, at least in part, by heterotetrameric ERG channels. This suggestion is demonstrated to occur for ERG1A/ERG1B by showing that the two isoforms coassemble in mouse brain.
Guasti
Leonardo
L
Department of Experimental Pathology and Oncology, University of Firenze, 50031 Firenze, Italy.
Cilia
Emanuele
E
Crociani
Olivia
O
Hofmann
Giovanna
G
Polvani
Simone
S
Becchetti
Andrea
A
Wanke
Enzo
E
Tempia
Filippo
F
Arcangeli
Annarosa
A
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism*; D020033:Protein Isoforms; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D014018:Tissue Distribution
D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606915:Kcnh2 protein, mouse; D020033:Protein Isoforms