1933
The activity of the immunoglobulin heavy-chain (IgH) enhancer is restricted to B cells , although it binds both B-cell-restricted and ubiquitous transcription factors .
 ( cell type: B cells, None) , ( DNA: immunoglobulin heavy-chain (IgH) enhancer, 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:
 ( cell type: B cells, None) , ( DNA: immunoglobulin heavy-chain (IgH) enhancer, None) 