Fig. 4
Cre RNA injection into stable transgenic rag2-loxP-dsRED2-loxP-EGFP-mMyc fish leads to transgene recombination and rapid onset of Myc-induced T-ALL. (A) Diagram of rag2-loxP-dsRED2-loxP-EGFP-mMyc construct. (B) Thymocytes from a 73-day-old rag2-lox-dsRED2-EGFP-mMyc transgenic fish are red-fluorescent-labeled in the absence of Cre expression. (C) PCR of genomic DNA isolated from blood cells of WT control or transgenic rag2-loxP-dsRED2-loxP-EGFP-mMyc (LDL-EMyc) fish. rag2 primers amplify genomic DNA, mMyc primers amplify the mMyc transgene, and Lox primers amplify either a 1.7-kb nonrecombined fragment (Lox-NR) or a 0.4-kb fragment, which results when Cre recombination has occurred (Lox-Rec). (D and E) One-cell-stage rag2-loxP-dsRED2-loxP-EGFP-mMyc embryos were injected with the Cre RNA (25 ng/μl) and grown to 51 days of development, at which time they had both GFP- and dsRED2-labeled (D) or GFP-positive alone (E) leukemias. The same fish is shown, right (D) and left (E) side. Images are composites of dsRED2 and GFP fluorescence and bright-field images. |