7720
Furthermore, pre-B cell and plasma cell lines were Spi-C -negative , suggesting that Spi-C might be a regulatory molecule during a specific phase of B lymphoid development .
 ( protein: Spi-C, None) , ( protein: regulatory molecule, None) , ( protein: Spi-C, 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:
 ( protein: Spi-C, None) , ( protein: regulatory molecule, None) , ( protein: Spi-C, None) 