Effect of antisense chop oligodeoxynucleotides on normal murine erythropoiesis in vitro. (A) CFU-E–derived colony growth. (B) BFU-E–derived colony growth. (•) Antisense oligos; (○) missense oligos. Note the specific concentration-dependent inhibition of CFU-E colony formation by antisense chop oligos. Each point is the mean of duplicate determinations.