Development of transposon-mediated GAL4 gene and enhancer trap methods and production of abnormal behavioral phenotype by targeted expression of tetanus toxin light chain in zebrafish .

Asakawa, K.1 , Mizusawa, K.1 , Urasaki, A.1 , Kotani, T.1 , Nagayoshi, S.1 , Kishimoto, Y.1 , Hibi, M.2 , Kawakami, K.1

1. National Institute of Genetics, 2. RIKEN CDB

 We created the Tol2 transposon constructs for GAL4 gene and enhancer trapping. A modified GAL4 gene was placed downstream of rabbit β-globin splice acceptor for gene trapping (SA-gal4) and the zebrafish hsp70 promoter for enhancer trapping (hsp-gal4). Then, we created random insertions of these Tol2 constructs in the genome. By crossing the SA-gal4 fish or the hsp-gal4 fish with the UAS-EGFP fish, we isolated 206 GAL4 lines based on unique GFP expression patterns.
 To test if these GAL4 lines can be used to modulate neuronal functions, we constructed the transgenic fish carrying a gene for tetanus toxin light chain (TeTxLC), which blocks neurotransmitter release via synaptic vesicles, downstream of UAS. We identified 9 GAL4 lines that showed a touch response defect when crossed with the UAS-TeTxLC line. We think that in such lines the Gal4 was expressed in neurons that are involved in the touch response and synaptic transmission of such neurons was blocked by induction of TeTxLC.