145
Two consensus sequences, called X and Y boxes , capable of binding nuclear proteins and regulating expression in B cells have been defined within the immediate upstream region of major histocompatibility complex (MHC) class II promoters .
 protein: nuclear proteins; DNA: major histocompatibility complex (MHC) class II promoters; cell type: B cells
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: nuclear proteins; DNA: major histocompatibility complex (MHC) class II promoters; cell type: B cells