Heme degradation pathway characterization during E/Meg development. (A) E/Meg-restricted expression of the heme degradation pathway genes using in silico data.²¹  A log₂ signal intensity <6 is considered background expression. Cell lineage abbreviations are provided in supplemental Table 2. (B-C) Expression patterns of heme degradation pathway genes were quantified by qPCR using human CD34⁺ cells differentiated along (B) erythroid (Epo) or (C) megakaryocytic (Tpo) lineages; Tpo-directed cultures include Platelet Factor 4 (PF4) and c-MPL transcripts as lineage markers. All results are expressed as actin-normalized means ± standard error of the mean (SEM) from triplicate experiments. (D-E) RNA levels (normalized reads per kilobase of transcript per million reads) of heme degradation pathway genes from (D) ET (N = 7) and normal (N = 5) platelets or as (E) quantified by qPCR (ET, N = 5; normal, N = 5); *P < .05.