Regulated expression of human globin genes following transfer with retroviral vectors

We have constructed retroviral vectors containing human globin genes (gamma-beta hybrid gene or beta globin gene) and have transferred these into mouse erythroleukemia cells and obtained regulated expression of human globin mRNA and protein. The level of human globin mRNA production is high (7-40% of endogenous mouse beta major mRNA) and human beta-globin chain production is also relatively high in these cells (see Karlsson et al, 1987, for details). Production of gamma-beta hybrid chains in the virally transduced cells is low despite high mRNA levels. This is due to instability of the gamma-beta chain and possibly also because the viral transcript can act as antisense globin RNA and reduce protein production. Some of our globin viruses have a high titer (up to 2 X 10(6) c.f.u./ml) and may be useful in transferring globin genes into bone marrow stem cells.