Flow cytometry analysis of zebrafish whole kidney marrow from a marrow transplant recipient. Zebrafish transplant recipients were irradiated and injected with 5 × 10⁵ marrow cells from a transgenic β-actin:GFP donor. Whole kidney marrow from a representative recipient was dissected 3 months later and analyzed by flow cytometry. (a) The forward scatter (FSC) versus side scatter (SSC) profile of zebrafish whole kidney marrow shows four cell populations: erythroid, lymphoid, myeloid, and precursor cells. (b) Histograms for GFP expression of cells within the lymphoid, myeloid and precursor gates show multilineage engraftment with GFP⁺ donor cells (blue lines). The red lines show GFP expression in a wild-type-negative control fish.

Direct visualization of engrafted GFP⁺ and mCherry⁺ marrow donor cells in casper recipients. 40 × 10³ WKM cells from a transgenic ubiquitin:GFP donor were mixed with 80 × 10³ WKM cells from a transgenic ubiquitin:mCherry donor and injected into the circulation of a casper recipient fish. The photos are taken 4 weeks after transplantation and show engraftment of (a) GFP⁺ and (b) mCherry⁺ cells in the kidney (white arrows).

Survival of different zebrafish lines in response to radiation. Kaplan-Meier survival curves are shown for four different zebrafish strains after irradiation with a total dose of 25 Gy, delivered in two equal fractions of 12.5 Gy separated by 24 hours. Twenty one fish were irradiated in each group. CG1 is a clonal homozygous diploid fish line generated by parthenogenesis [21, 38]. UDA, UXA2, and UBA are inbred zebrafish lines derived from a single mating pair of AB parents [35]. Each line was named for the homozygous class I MHC gene at its chromosome 19 locus. The results demonstrate 100% mortality for the CG1 fish by day 22, and by day 37 for the UDA fish. In contrast, the UBA and UXA2 fish lines both had approximately 80% survival at 40 days after irradiation.