Globin mRNA species induced in Ba/F3 cells by various chemical inducers analyzed by RNase protection assays. RNA samples prepared from nontreated and chemically induced Ba/F3 cells were analyzed as described in Fig 3. Note that Ba/F3 cells belonging to the diffuse haplotype produced the 245-base–protected fragment of βh1 mRNA, which is longer than the protected fragment derived from B6SUtA cells, as discussed in detail in the text.