Bertrand, C., Chatonnet, A., Takke, C., Yan, Y.-L., Postlethwait, J., Toutant, J.P., and Cousin, X. (2001) Zebrafish Acetylcholinesterase Is Encoded by a Single Gene Localized on Linkage Group 7: Gene structure and polymorphism; molecular forms and expression pattern during development. The Journal of biological chemistry. 276(1):464-474.
We cloned and sequenced the acetylcholinesterase gene and cDNA of zebrafish, Danio rerio. We found a single gene (ache) located on linkage group LG7. Relative organization of ache, eng2 and shh genes is conserved between zebrafish and mammals and defines a synteny. Restriction fragment length polymorphism analysis allowed to identify several allelic variations. We also identified two transposable elements in non-coding regions of the gene. Compared to other vertebrate acetylcholinesterase genes, ache gene contains no alternative splicing at 5? or 3' ends where only a T exon is present. The translated sequence is 60 to 80 % identical to vertebrates acetylcholinesterases and exhibits an extra loop specific to teleosts. Analysis of molecular forms showed a transition, at the time of hatching, from globular G4 form to asymmetric A12 form which becomes prominent in adults. In situ hybridization and enzymatic activity detection on whole embryos confirmed early expression of the acetylcholinesterase gene in nervous and muscular tissues. We found no butyrylcholinesterase gene or activity in Danio. These findings make zebrafish a promising model to study function of AChE during development and regulation of molecular forms assembly in vivo.