title: A role for transcription factor glial cell missing 2 in Ca2+ homeostasis in zebrafish, Danio rerio.
abstract: The present study investigated the role of the transcription factor, glial cell missing 2 (gcm2), in Ca(2+) regulation in zebrafish larvae. Translational gene knockdown of gcm2 decreased Ca(2+) uptake and the density of ionocytes expressing the epithelial Ca(2+) channel (ecac), and disrupted the overall Ca(2+) balance. Ca(2+) uptake and the expression of gcm2 messenger RNA (mRNA) were significantly elevated in larvae acclimated to low Ca(2+) water (25 μM); the stimulation of Ca(2+) uptake was not observed in fish experiencing gcm2 knockdown. Acclimation to acidic water (pH 4) significantly reduced whole-body Ca(2+) content owing to reduced Ca(2+) uptake and increased Ca(2+) efflux. However, ecac mRNA levels and the density of ecac-expressing ionocytes were increased in fish acclimated to acidic water, and maximal Ca(2+) uptake capacity (J MAX) was significantly increased when measured in control water (pH ~7.4). Acclimation of larvae to acidic water significantly increased gcm2 mRNA expression, and in gcm2 morphants, no such stimulation in Ca(2+) uptake was observed after their return to control water. Overexpression of gcm2 mRNA resulted in a significant increase in the numbers of ecac-expressing ionocytes and Ca(2+) uptake. These observations reveal a critical role for gcm2 in Ca(2+) homeostasis in zebrafish larvae.
authors.affiliation: Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6 N5, Canada.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kumai
authors.forename: Raymond W M
authors.initials: RW
authors.lastname: Kwong
authors.forename: Steve F
authors.initials: SF
authors.lastname: Perry
mesh_terms: D000064:Acclimatization; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D050916:TRPV Cation Channels; D014157:Transcription Factors; D029961:Zebrafish Proteins; C501172:gcm2 protein, zebrafish; C505134:trpv6 protein, zebrafish; D002118:Calcium