11851
However, in differentiating erythroid cells , which must incorporate high levels of iron to sustain hemoglobin synthesis , and in macrophages , which are involved in iron storage, transcriptional regulation seemed to be a relevant mechanism.
 ( protein: hemoglobin, None) , ( cell type: macrophages, None) , ( cell type: differentiating erythroid cells, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: hemoglobin, None) , ( cell type: macrophages, None) , ( cell type: differentiating erythroid cells, None) 