Legend to Fig 3 - Neo directed phosphotransferase activity and expression of the 
human ADA enzyme in NIH 3T3 cells infected with ADA containing vectors * A. The 
presense of the Tn5 encoded phosphotransferase activity in cell extracts of NIH 
3T3 cells was determined according to the procedure of Reiss et.al (14). Lane 
3T3 — Cell lysates derived from NIH 3T3 cells showing no phosphotransferase 
activity. The rest of the lanes show the phosphotransferase activity in NIH 3T3 
cells infected with various retroviral vectors as indicated (structures shown in 
Fig 1). 
B. Presence of human ADA activity in mouse cells was determined by starch gel 
electrophoresis of cell extracts followed by in situ chemical staining for the 
human and mouse ADA isozymes (17). Each lane represents 2x10^ cells. CEM, a 
human T-cell line, shows the migration of the human ADA isozymes which can be 
separated from the mouse ADA isozyme present in NIH 3T3 cells (lane 3T3). The 
rest of the lanes are NIH 3T3 cells infected with various virus preparations as 
indicated (see Fig 1 for structures). 
Recombinant DNA Research, Volume 12 
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