Figure 4.
The Lnk SH2 domain is required to inhibit Epo-dependent erythroblast survival in in vitro culture. Ter119- fetal liver erythroid progenitor cells were purified, infected, and cultured as described in “Materials and methods.” We then introduced either the control vector or the wild-type or mutant Lnk cDNA constructs into Ter119- erythroid progenitors. (A) Average cell numbers (± SD) at the end of 48-hour culture. The numbers were normalized to the starting culture density of 1 × 105/mL. (B) At 40 hours after initiation of the culture, the erythroblasts were stained for annexin V and 7-AAD, and subjected to FACS analysis. hCD4+ fractions (ie, infected cells) were gated in all the FACS plots. The apoptotic cell fractions (annexin V+ and 7-AAD-) and dead cell fractions (annexin V+ and 7-AAD+) are indicated in each panel.