6478
Furthermore, introduction of exogenous GATA-1 in both MEL cells and Xenopus embryos and explants relieves the block to erythroid differentiation imposed by PU.1 .
 protein: PU.1; cell line: MEL cells; protein: GATA-1
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: PU.1, MEL cells, GATA-1 
Answer:
 protein: PU.1; cell line: MEL cells; protein: GATA-1