Human γ_c can functionally cooperate with murine IL-7R in mediating the response to murine IL-7. 293T cells were transfected with expression vectors for Jak3, Stat5a, Stat5b, and the following: murine IL-7R alone (lanes 1 and 2), murine IL-7R + murine γ_c (lanes 3 and 4), or murine IL-7R + human γ_c (lanes 5 and 6). Forty-eight hours later, they were not stimulated (lanes 1, 3, and 5) or stimulated with 1 nmol/L murine IL-7 (lanes 2, 4, and 6). Nuclear extracts were prepared and EMSAs performed using the PRRIII probe corresponding to the IL-2 response element in the human IL-2R gene.37