Structure of chimeric receptors and factor responsiveness of FDC-P1 transfectants.

(A) Shown schematically are the wild type δ1 and EPOR together with the chimeras hEPO-δ1R, hEDER, and hMPL-δ1R. Fused domains are designated by restriction sites generated within cognate cDNAs. (B) Time course of growth of the FDC-P1 cells retrovirally transduced with various receptor constructs. Parental FDC-P1 and FDC-P1 cells expressing hEPOR, hEPOR-δ1R, EDER, and hMPL-δ1R were cultivated in the presense of 1 ng/mL of mIL-3, 2 U/mL of hEPO, 2 U/mL of hEPO, 2 U/mL of hEPO, and 100 ng/mL of hTPO, respectively, and the cell number was counted at the indicated times.