Northern blot analysis of G-CSFR in D⁺ cells treated with various concentrations of ATRA for 48 hours or after 24, 48, or 72 hours' exposure to 7 μmol/L ATRA.

(A) 48 hours, various concentrations. (B) Exposure to 7μmol/L ATRA. Ethidium bromide fluorescence of the gel before transfer shows the presence of approximately equal amounts of RNA. C indicates untreated control; R, ATRA treated.