Expression and functional analysis of Na(+)-dependent glutamate transporters from zebrafish brain.
High-affinity excitatory amino acid transporters (EAATs) regulate extracellular glutamate levels. Zebrafish (Danio rerio) provides an excellent model to study the function of different neurotransmitter systems. Although the identification of the EAAT family is well established in the mammalian central nervous system (CNS), EAAT-related genes and their expression profile in zebrafish have not yet been reported. Here we identify and describe the expression profile of EAATs-related genes and functional properties of glutamate uptake in three major brain structures from zebrafish (telencephalon, optic tectum and cerebellum). Searches on zebrafish genome databases and a phylogenetic analysis confirmed the presence of several EAAT-related genes (EAAT2, EAAT3, three EAAT1 paralogs and two EAAT5 sequences). All sequences identified were expressed in the structures analyzed. EAAT2 and EAAT3 were the most prominent glutamate transporters expressed in all brain areas. A uniform expression was observed for EAAT1A, whereas higher EAAT1B transcript levels were detected in telencephalon. Lower amounts of EAAT1C transcripts were observed in cerebellum when compared to other structures. No EAAT4-related sequence was found in the zebrafish genome. The EAAT5A expression was similar to EAAT5B in the telencephalon, while EAAT5B was less expressed than EAAT5A in optic tectum and cerebellum. Moreover, the glutamate uptake was significantly higher in optic tectum, which indicates functional differences within zebrafish brain structures. Altogether, the study of glutamate uptake in zebrafish could be important to evaluate the modulation of glutamatergic signaling through pharmacological and toxicological studies.
Rico
Eduardo Pacheco
EP
Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brazil. eduprico@gmail.com
de Oliveira
Diogo Losch
DL
Rosemberg
Denis Broock
DB
Mussulini
Ben Hur
BH
Bonan
Carla Denise
CD
Dias
Renato Dutra
RD
Wofchuk
Susana
S
Souza
Diogo Onofre
DO
Bogo
Maurício Reis
MR
D000818:Animals; D002531:Cerebellum / Q000378:metabolism*; D030541:Databases, Genetic; D005260:Female; D020869:Gene Expression Profiling; D050491:Glutamate Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D012964:Sodium / Q000378:metabolism; D013477:Superior Colliculi / Q000378:metabolism*; D013687:Telencephalon / Q000378:metabolism*; D013997:Time Factors; D015027:Zebrafish / Q000378:metabolism*
D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid; D012964:Sodium