1748
Here we examine molecular mechanisms controlling the pattern of alpha 4 expression .
 protein: alpha 4
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: alpha 4 
Answer:
 protein: alpha 4