RT-PCR Southern blot analysis of FucT-IV and FucT-VII mRNA expression in K562 transfectants. Essentially equivalent FucT-IV levels are seen in the K562 parents and transfectants, which are lower than the FucT-IV level in HL60 cells. Note that the FucT-VII level in K562/FucT-VII cells is greater than in K562/PSGL-1/FucT-VII cells, corresponding to the levels of surface sLex (see Fig 1). Untransfected K562 cells and K562/PSGL-1 cells express no detectable FucT-VII.