Functional characterization of lmo2‐Cre transgenic zebrafish

Cre/loxP system is a powerful tool to manipulate the genome. Transgenic animals expressing Cre recombinase in specific tissues or cells have been widely used for conditional gene targeting, lineage tracing, and other genetic analyses. In zebrafish, the transgenic line with stable expression of Cre in specific tissues and cell subtypes has not been generated and its functional activity remains to be defined. Here we report the establishment of a stable transgenic fish Tg(zlmo2:Cre), which specifically expresses Cre in the primitive hematopoietic progenitors and vascular endothelial cells, under the control of lmo2 promoter. Our result shows that the Cre expression pattern recapitulates the endogenous lmo2 expression pattern during embryogenesis. Crossing of the Tg(zlmo2:Cre) line with another established transgenic reporter line Tg(zlmo2:loxP‐DsRed‐loxP‐EGFP), induces a robust recombination activity in hematopoietic progenitors and vascular endothelial cells. Thus, the Tg(zlmo2:Cre) transgenic line provides an invaluable tool to dissect genetic pathways in hematopoietic development and diseases. Developmental Dynamics 237:2139–2146, 2008. © 2008 Wiley‐Liss, Inc.