Hsu, K., Traver, D., Kutok, J.L., Hagen, A., Liu, T.X., Paw, B.H., Rhodes, J., Berman, J., Zon, L.I., Kanki, J.P., and Look, A.T. (2004) The pu.1 promoter drives myeloid gene expression in zebrafish. Blood. 104(5):1291-1297.
Pu.1 is a member of the ets family of transcription factors and plays an essential role in the development of both myeloid and lymphoid cells. To examine zebrafish Pu.1 (zpu.1) expression in subpopulations of blood cells during zebrafish development, we linked a 9-kilobase zebrafish genomic fragment upstream of the zpu.1 initiator codon to green fluorescent protein (GFP) and microinjected this construct to generate stable transgenic lines. GFP-positive, fluorescent myeloid precursors were observed migrating from the antero-lateral mesoderm in living embryos from 16 to 28 hours post-fertilization (hpf), in a pattern that overlaps the expression pattern of endogenous zpu.1 mRNA. Analysis of larval histologic sections revealed GFP-expressing hematopoietic cells in the developing zebrafish kidney. Flow cytometric analysis of cells from adult whole kidney marrow revealed two discrete subpopulations of GFP-positive cells, which after cell sorting exhibited either myeloid or early lymphoid morphology. Thus, the zebrafish zpu.1 promote fragment employed here is capable of driving reporter gene expression in subsets of embryonic and adult hematopoietic cells. These transgenic lines will be useful to dissect the cellular and molecular control of myeloid cell differentiation, and this promote fragment may prove useful in the development of zebrafish models of acute myeloid leukemia.