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Expression of the human RAR-alpha in receptor-negative erythroblasts conferred RA -induced regulation of differentiation to the otherwise unresponsive cells , thus showing that the RAR-alpha is essential for the RA effect .
 protein: RAR-alpha; cell type: unresponsive cells; protein: human RAR-alpha; cell line: receptor-negative erythroblasts; protein: RAR-alpha
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 protein: RAR-alpha; cell type: unresponsive cells; protein: human RAR-alpha; cell line: receptor-negative erythroblasts; protein: RAR-alpha