Effects of the expression of full-length and mutant G-CSFR on WEHI-3B D⁺ cell growth after treatment with 10 ng/mL of rhG-CSF. Untreated and G-CSF–treated cells were seeded at 5 × 10⁴ cells/mL, and their cell densities were determined daily for 3 days. I, D⁺V (vector-transfected cells); II, D⁺GR95 (full-length G-CSFR–transfected cells); III-VIII, D⁺GR-A, D⁺GR-B, D⁺GR-C, D⁺GR-D, D⁺GR-E, and D⁺GR-F (truncated G-CSFR–transfected cells). Each value is the average of three independent experiments ± standard deviation. (Note: When standard deviations are very small, the error bars may not be clearly visible in the graphs.)