We also use Gateway cloning to assay promoter or enhancer elements in zebrafish. Our approach is based on similar techniques used in the C. elegans community (Hope et al. 2004; Deplancke et al. 2004). For this purpose, we generate ENTRY plasmids containing promoter elements flanked by attL4 and attR2 sites. You can use any attL1/attL2 flanked transgene as a reporter (in this example, we show generation of an egfp reporter). Usually, you will already have standard transgene L1/L2 entry clones available.