Analysis of pancreatic development in living transgenic zebrafish embryos

Using DNA constructs containing regulatory sequences of the zebrafish Pdx-1 and insulin genes, germline transgenic zebrafish expressing the green fluo rescent protein (GFP) reporter gene in the pancreas were generated. For bot h constructs, the GFP expression patterns in transgenic embryos were consis tent with the mRNA expression patterns detected by RNA in situ hybridizatio n. A deletion promoter analysis revealed that positive and negative cis-act ing elements were involved in regulation of insulin gene expression. Three- dimensional reconstructions imaged from living embryos using two-photon las er-scanning microscopy (TPLSM) demonstrated that the zebrafish pancreas is formed from a single dorsal pancreatic cell mass. This is in contrast to ma mmals where the pancreas derives from both dorsal and ventral anlage. These transgenic fish should be useful for in vivo studies of factors involved i n specifying and regulating pancreatic development and function. (C) 2001 E lsevier Science Ireland Ltd. All rights reserved.