NCI-Frederick Laboratory Animal Sciences Program 1 article published in JoVE Cancer Research Co-Culture and Transduction of Murine Thymocytes on Delta-Like 4-Expressing Stromal Cells to Study Oncogenes in T-Cell Leukemia Gisele O. L. Rodrigues1, WenQing Li1, Sarah D. Cramer1,2,3, Hila Y. Winer1, Tu Chun Hsu1,2,3, Timothy Gower4, Julie A. Hixon1, Scott K. Durum1 1Cytokines and Immunity Section, Cancer Innovation Laboratory, National Cancer Institute, National Institutes of Health, 2Comparative Biomedical Scientist Training Program, NIH, 3Department of Pathobiology and Diagnostic Investigation, Veterinary Diagnostic Laboratory, Michigan State University, 4NCI-Frederick Laboratory Animal Sciences Program This protocol describes the isolation of double-negative thymocytes from the mouse thymus followed by retroviral transduction and co-culture on the delta-like 4-expressing bone marrow stromal cell line co-culture system (OP9-DL4) for further functional analysis.